Intel(R) C Compiler 9.1 for Itanium(R)-based applications
Intel(R) Fortran Compiler 9.1 for Itanium(R)-based applications
---------------------------------------------
NAMES
icc - invokes the Intel(R) C++ compiler
ifort - invokes the Intel(R) Fortran Compiler
pexec - tools to control placement of
processes on CPUs
SYNOPSIS
icc [ options ] file1 [ file2 ...] where:
options
represents zero or more compiler options.
filen is a C/C++ source (.C .c .cc .cp .cpp .cxx .c++ .i), assembly
(.s), object (.o), static library (.a), or other linkable file.
Note: The icpc command uses the same compiler options as the icc com-
mand. Invoking the compiler using icpc compiles .c, and .i files as
C++. Invoking the compiler using icc compiles .c and .i files as C.
Using icpc always links in C++ libraries. Using icc only links in C++
libraries if C++ source is provided on the command line.
DESCRIPTION
The Intel(R) C++ Compiler is designed to process C and C++ programs on
Intel architecture based systems. You can preprocess, compile, assem-
ble, and link these programs.
This document explains how information and instructions apply differ-
ently to IA-32 applications, Intel(R) EM64T applications, and Ita-
nium(R) architecture-based applications. If a description does not
explicitly state a specific architecture, it is applicable to all.
See the Intel C++ Compiler user documentation for more complete infor-
mation than is presented here.
Most language features are available on all supported systems. How-
ever, some language features are only available on certain processors
or a certain operating system. Such language features are labeled
within parenthses as follows:
i32 Means the feature is available on IA-32-based systems.
i32em Means the feature is available on IA-32-based systems with
Intel(R) Extended Memory 64 Technology (Intel(R) EM64T).
i64 Means the feature is available on Itanium(R)-based systems.
L*X Means the feature is available on Linux* systems.
M*X32 Means the feature is available on Intel(R)-based systems run-
ning Mac OS*.
If a labeled feature is only available on certain processors or oper-
ating systems, you will see the word ( only) within the label along
with the appropriate abbreviation(s). If a labeled feature is not
available on a certain processor or operating system, you will see the
words (not on ) within the label along with the appropriate abbrevia-
tion. If no label appears, the feature is available on all supported
systems.
gcc* Interoperability
C++ compilers are interoperable if they can link object files and
libraries generated by one compiler with object files and libraries
generated by the second compiler, and the resulting executable runs
successfully. The Intel(R) C++ Compiler options that affect gcc*
interoperability include:
· -cxxlib-<mode>
· -gcc-name
· -gcc-version
· -fabi-version
· -no-gcc (see gcc Predefined Macros for more information)
· -[no-]gcc-extern-inline
In the 9.1 compiler, there is improved compatibility with gcc regard-
ing the behavior of extern inline functions. Previously, by default,
the C99 standard was followed by always creating a body for extern
inline functions. In 9.1, by default, no body is created unless the
function cannot be inlined for some reason (for example, its address
might be taken). If the C99 behavior, rather than the now default gcc
behavior is desired, use the -no-gcc-extern-inline option.
The Intel(R) C++ Compiler is interoperable with GNU gcc* compiler ver-
sions greater than or equal to 3.2. See the Intel C++ Compiler User's
Guide for more information.
OPTION SUMMARIES
Option Alphabetic Summary
All of the Intel C++ Compiler options are listed alphabetically in
this section. After each listing is a reference to the Functional
area where a detailed description of the option appears.
-A- see Preprocessor Options
-A<name>[<value(s)>]
see Preprocessor Options
-[no-]alias-args see Advanced Performance Options
-[no]align see Language Options
-ansi see Language Options
-[no-]ansi-alias see Advanced Performance Options
-auto-ilp32 see Advanced Performance Options
-ax{K|W|N|B|P} see Performance Options, Optimization Levels,
Automatic Processor-specific Optimization,
Vectorization Options
-B<dir> see Miscellaneous Options
-c see Output, Debug, and PCH Options
-C see Preprocessor Options
-[no-]c99 see Language Options
-[no-]clomp-sharable-info
see Advanced Performance Options, Paral-
lelization with OpenMP*
-[no-]clomp-sharable-propagation
see Advanced Performance Options, Paral-
lelization with OpenMP*
-[no-]cluster-openmp-profile
see Advanced Performance Options, Paral-
lelization with OpenMP*
-[no-]cluster-openmp
see Advanced Performance Options, Paral-
lelization with OpenMP*
-[no-]complex-limited-range
see Advanced Performance Options
-create-pch <file>
see Output, Debug, and PCH Options; Precom-
piled Headers
-cxxlib-<mode> see Linking or Linker Options
-D<name>[=<value>]
see Preprocessor Options
-[no-]debug [keyword]
see Output, Debug, and PCH Options
-dD see Preprocessor Options
-dM see Preprocessor Options
-dN see Preprocessor Options
-dryrun see Miscellaneous Options
-dynamic-linker<filename>
see Linking or Linker Options
-dynamiclib see Linking or Linker Options
-E see Preprocessor Options
-EP see Preprocessor Options
-export see Language Options
-export-dir <dir> see Language Options
-F<dir> see Mac OS Options
-fabi-version=<value>
see Miscellaneous Options
-f[no-]alias see Performance Options
-fargument-[no-]alias
see Advanced Performance Options
-fargument-noalias-global
see Advanced Performance Options
-fast see Performance Options, Optimization Levels
-fcode-asm see Output, Debug, and PCH Options
-f[no-]common see Miscellaneous Options
-fdata-sections see Performance Options
-f[no-]exceptions see Performance Options
-f[no-]fnalias see Performance Options
-ffunction-sections
see Performance Options
-f[no-]inline see Performance Options
-f[no-]inline-functions
see Performance Options
-finline-limit=<n>
see Performance Options
-f[no-]math-errno see Miscellaneous Options
-fminshared see Miscellaneous Options
-fno-builtin see Miscellaneous Options
-fno-builtin-<func>
see Performance Options, Miscellaneous
Options
-fno-gnu-keywords see Language Options
-fno-implicit-inline-templates
see Language Options
-fno-implicit-templates
see Language Options
-f[no-]omit-frame-pointer
see Performance Options
-f[no-]non-lvalue-assign
see Language Options
-fno-operator-names
see Language Options
-[no-]fnsplit see Advanced Performance Options
-fp see Performance Options
-fpack-struct see Miscellaneous Options
-fpascal-strings see Mac OS Options
-fpermissive see Language Options
-f[no-]pic see Miscellaneous Options
-f[no-]PIC see Miscellaneous Options
-fp-model <name> see Advanced Performance Options
-[no-]fp-port see Performance Options
-fpstkchk see Performance Options
-fr32 see Miscellaneous Options
-f[no-]rtti see Language Options
-freg-struct-return
see Miscellaneous Options
-fshort-enums see Language Options
-fsource-asm see Output, Debug, and PCH Options
-fstack-security-check
see Miscellaneous Options
-fsyntax-only see Language Options
-ftemplate-depth-<n>
see Language Options
-ftls-model=<model>
see Advanced Performance Options
-ftrapuv see Output, Debug, and PCH Options
-[no-]ftz see Advanced Performance Options
-funroll-loops see Advanced Performance Options
-funsigned-bitfields
see Language Options
-funsigned-char see Language Options
-f[no]verbose-asm see Output, Debug, and PCH Options
-fvisibility=[extern|default|protected|hidden|internal]
see Miscellaneous Options
-fvisibility-default=<file>
see Miscellaneous Options
-fvisibility-extern=<file>
see Miscellaneous Options
-fvisibility-hidden=<file>
see Miscellaneous Options
-fvisibility-internal=<file>
see Miscellaneous Options
-fvisibility-protected=<file>
see Miscellaneous Options
-g see Output, Debug, and PCH Options
-g0 see Output, Debug, and PCH Options
-[no-]gcc-extern-inline
see Miscellaneous Options
-gcc-name=<dir> see Miscellaneous Options
-gcc-version=<nnn>
see Miscellaneous Options
-[no-]global-hoist
see Miscellaneous Options
-H see Preprocessor Options
-help see Miscellaneous Options
-I<dir> see Preprocessor Options
-idirafter<dir> see Preprocessor Options
-i-dynamic see Linking or Linker Options
-imacros <file> see Preprocessor Options
-inline-debug-info
see Output, Debug, and PCH Options
-inline-factor see Advanced Performance Options
-inline-forceinline
see Advanced Performance Options
-inline-max-per-compile
see Advanced Performance Options
-inline-max-per-routine
see Advanced Performance Options
-inline-max-size see Advanced Performance Options
-inline-max-total-size
see Advanced Performance Options
-inline-min-size see Advanced Performance Options
-ip see Advanced Performance Options, Interproce-
dural Optimizations (IPO)
-[no-]IPF-fltacc see Advanced Performance Options
-IPF-flt-eval-method0
see Advanced Performance Options
-[no-]IPF-fma see Advanced Performance Options
-[no-]IPF_fp_relaxed
see Advanced Performance Options
-IPF-fp-speculation{fast|safe|strict|off}
see Advanced Performance Options
-ip-no-inlining see Advanced Performance Options
-ip-no-pinlining see Advanced Performance Options
-ipo[value] see Advanced Performance Options, Interproce-
dural Optimizations (IPO)
-ipo-c see Advanced Performance Options, Interproce-
dural Optimizations (IPO)
-ipo-S see Advanced Performance Options, Interproce-
dural Optimizations (IPO)
-ipo-separate see Advanced Performance Options, Interproce-
dural Optimizations (IPO)
-iprefix <prefix> see Preprocessor Options
-iquote<dir> see Preprocessor Options
-i-static see Linking or Linker Options
-isystem<dir> see Preprocessor Options
-ivdep-parallel see Advanced Performance Options
-iwithprefix <dir>
see Preprocessor Options
-iwithprefixbefore <dir>
see Preprocessor Options
-Kc++ see Language Options
-kernel see Miscellaneous Options
-l<dir> see Linking or Linker Options
-L<dir> see Linking or Linker Options
-long_double see Miscellaneous Options
-M see Preprocessor Options
-malign-double see Language Options
-malign-mac68k see Mac OS Options
-malign-natural see Mac OS Options
-malign-power see Mac OS Options
-map-opts see Output, Debug, and PCH Options
-march={pentiumpro | pentiumii | pentiumiii | pentium2 | pen-
tium3 | pentium4}
see Performance Options
-mcmodel=<mem_model>
see Linking or Linker Options
-mcpu={pentium | pentiumpro | pentium4 | itanium | itanium2 |
itanium2-p9000}
see Performance Options
-MD see Preprocessor Options
-mdynamic-no-pic see Mac OS Options
-MF<file> see Preprocessor Options
-mfixed-range=f12-f15,f32-f127
see Miscellaneous Options
-MG see Preprocessor Options
-m[no-]ieee-fp see Performance Options
-MM see Preprocessor Options
-MMD see Preprocessor Options
-mno-serialize-volatile
see Advanced Performance Options
-mp see Performance Options
-MP see Preprocessor Options
-mp1 see Performance Options
-MQ<target> see Preprocessor Options
-m[no-]relax see Linking or Linker Options
-mserialize-volatile
see Advanced Performance Options
-msse see Performance Options
-msse2 see Performance Options
-msse3 see Performance Options
-MT<target> see Preprocessor Options
-mtune=<cpu> see Performance Options
-[no-]multibyte-chars
see Miscellaneous Options
-nobss-init see Miscellaneous Options
-no-cpprt see Linking or Linker Options
-nodefaultlibs see Linking or Linker Options
-no-gcc see Preprocessor Options
-nostartfiles see Linking or Linker Options
-nostdinc see Preprocessor Options
-nostdlib see Linking or Linker Options
-o<file> see Output, Debug, and PCH Options
-O see Performance Options
-O0 see Performance Options, Optimization Levels
-O1 see Performance Options, Optimization Levels
-O2 see Performance Options, Optimization Levels
-O3 see Performance Options, Optimization Levels
-Ob<n> see Performance Options
-openmp see Advanced Performance Options, Paral-
lelization with OpenMP*
-openmp-profile see Advanced Performance Options, Paral-
lelization with OpenMP*
-openmp-report{0|1|2}
see Advanced Performance Options, Paral-
lelization with OpenMP*
-openmp-stubs see Advanced Performance Options, Paral-
lelization with OpenMP*
-opt-mem-bandwidth<n>
see Advanced Performance Options
-opt-report see Advanced Performance Options
-opt-report-file<file>
see Advanced Performance Options
-opt-report-help see Advanced Performance Options
-opt-report-level[{min|med|max}]
see Advanced Performance Options
-opt-report-phase{ipo|hlo|ilo|ecg|omp|all}
see Advanced Performance Options, Paral-
lelization with OpenMP*
-opt-report-routine<name>
see Advanced Performance Options
-Os see Performance Options
-p see Advanced Performance Options
-P see Preprocessor Options
-parallel see Advanced Performance Options, Auto Paral-
lelization Options
-par-report{0|1|2|3}
see Advanced Performance Options, Auto Paral-
lelization Options
-par-threshold[<n>]
see Advanced Performance Options, Auto Paral-
lelization Options
-pc{32|64|80} see Performance Options
-pch see Output, Debug, and PCH Options; Precom-
piled Headers
-pch-dir <dir> see Output, Debug, and PCH Options; Precom-
piled Headers
-[no-]prec-div see Performance Options
-[no-]prec-sqrt see Performance Options
-[no-]prefetch see Advanced Performance Options
-print-multi-lib see Output, Debug, and PCH Options
-prof-dir <dir> see Advanced Performance Options, Pro-
file-guided Optimizations (PGO)
-prof-file <file> see Advanced Performance Options, Pro-
file-guided Optimizations (PGO)
-prof-gen[x] see Advanced Performance Options, Pro-
file-guided Optimizations (PGO)
-prof-gen-sampling
see Advanced Performance Options, Pro-
file-guided Optimizations (PGO)
-prof-use see Advanced Performance Options, Pro-
file-guided Optimizations (PGO)
-Qinstall <dir> see Component Control Options
-Qlocation,<tool>,<path>
see Component Control Options
-Qoption,<tool>,<optlist>
see Component Control Options
-qp see Advanced Performance Options
-rcd see Performance Options
-reserve-kernel-regs
see Miscellaneous Options
-[no]restrict see Language Options
-S see Output, Debug, and PCH Options
-shared see Linking or Linker Options
-shared-libcxa see Linking or Linker Options
-[no-]sox see Miscellaneous Options
-ssp see Advanced Performance Options
-static see Linking or Linker Options
-static-libcxa see Linking or Linker Options
-std=c99 see Language Options
-strict-ansi see Language Options
-T <file> see Linking or Linker Options
-tcheck see Advanced Performance Options
-[no]traceback see Compiler Diagnostics Options
-u <symbol> see Linking or Linker Options
-U<name> see Preprocessor Options
-unroll<n> see Advanced Performance Options
-unroll0 see Advanced Performance Options
-use-asm see Output, Debug, and PCH Options
-use-msasm see Output, Debug, and PCH Options
-use-pch <file> see Output, Debug, and PCH Options; Precom-
piled Headers
-V see Miscellaneous Options
-v see Miscellaneous Options
-vec-report[{0|1|2|3|4|5}]
see Advanced Performance Options
--version see Miscellaneous Options
-w see Compiler Diagnostics Options
-w<n> see Compiler Diagnostics Options
-Wa<o1>[,<o2>,...]
see Linking or Linker Options
-W[no-]abi see Compiler Diagnostics Options
-Wall see Compiler Diagnostics Options
-Wbrief see Compiler Diagnostics Options
-Wcheck see Compiler Diagnostics Options
-W[no-]comment[s] see Compiler Diagnostics Options
-Wcontext-limit=<n>
see Compiler Diagnostics Options
-wd<L1>[,<L2>,...]
see Compiler Diagnostics Options
-W[no-]deprecated see Compiler Diagnostics Options
-we<L1>[,<L2>,...]
see Compiler Diagnostics Options
-Werror see Compiler Diagnostics Options
-Winline see Compiler Diagnostics Options
-Wl,<o1>[,<o2>,...]
see Linking or Linker Options
-W[no-]main see Compiler Diagnostics Options
-W[no-]missing-prototypes
see Compiler Diagnostics Options
-wn<n> see Compiler Diagnostics Options
-Wp64 see Compiler Diagnostics Options
-Wp,<o1>[,<o2>,...]
see Linking or Linker Options, Precompiled
Headers
-W[no-]pointer-arith
see Compiler Diagnostics Options
-wr<L1>[,<L2>,...]
see Compiler Diagnostics Options
-W[no-]return-type
see Compiler Diagnostics Options
-W[no-]shadow see Compiler Diagnostics Options
-W[no-]uninitialized
see Compiler Diagnostics Options
-W[no-]unknown-pragmas
see Compiler Diagnostics Options
-W[no-]unused-function
see Compiler Diagnostics Options
-ww<L1>[,<L2>,...]
see Compiler Diagnostics Options
-X see Preprocessor Options
-x <type> see Miscellaneous Options
-x{K|W|N|B|P} see Performance Options, Optimization Levels,
Optimizing Exclusively for Specific Proces-
sors, Vectorization Options
-Xlinker <val> see Linking or Linker Options
-Zp[n] see Language Options
Option Functional Summary
All the options listed in the following summary are described
in more detail in the sections that follow.
Performance Options
-ax{K|W|N|B|P} -f[no-]alias -fast -fdata-sections
-f[no-]exceptions -f[no-]fnalias -ffunction-sections
-f[no-]inline -f[no-]inline-functions -fin-
line-limit=<n> -fno-builtin-<func>
-f[no-]omit-frame-pointer -fp -[no-]fp-port -fpstkchk
-march={pentiumpro | pentiumii | pentiumiii | pentium2 |
pentium3 | pentium4} -mcpu={pentium | pentiumpro | pen-
tium4 | itanium | itanium2 | itanium2-p9000}
-m[no-]ieee-fp -mp -mp1 -msse -msse2 -msse3
-mtune=<cpu> -O -O0 -O1 -O2 -O3 -Ob<n> -Os
-pc{32|64|80} -[no-]prec-div -[no-]prec-sqrt -rcd
-x{K|W|N|B|P}
Advanced Performance Options
-[no-]alias-args -[no-]ansi-alias -auto-ilp32
-[no-]clomp-sharable-info -[no-]clomp-sharable-propaga-
tion -[no-]cluster-openmp-profile -[no-]cluster-openmp
-[no-]complex-limited-range -fargument[no-]-alias -far-
gument-noalias-global -[no-]fnsplit -fp-model <name>
-ftls-model=<model> -[no-]ftz -funroll-loops
-inline-factor -inline-forceinline
-inline-max-per-compile -inline-max-per-routine
-inline-max-size -inline-max-total-size
-inline-min-size -ip -[no-]IPF-fltacc
-IPF-flt-eval-method0 -[no-]IPF-fma
-[no-]IPF_fp_relaxed -IPF-fp-specula-
tion{fast|safe|strict|off} -ip-no-inlining -ip-no-pin-
lining -ipo[value] -ipo-c -ipo-S -ipo-separate
-ivdep-parallel -mno-serialize-volatile -mserial-
ize-volatile -openmp -openmp-profile
-openmp-report{0|1|2} -openmp-stubs -opt-mem-band-
width<n> -opt-report -opt-report-file<file>
-opt-report-help -opt-report-level[{min|med|max}]
-opt-report-phaseipo|hlo|ilo|ecg|omp|all
-opt-report-routine<name> -p -parallel
-par-report{0|1|2|3} -par-threshold[<n>]
-[no-]prefetch -prof-dir <dir> -prof-file<file>
-prof-gen[x] -prof-gen-sampling -prof-use -qp -ssp
-tcheck -unroll<n> -unroll0
-vec-report[{0|1|2|3|4|5}]
Output, Debug, and PCH Options
-c -create-pch <file> -[no-]debug[keyword] -fcode-asm
-fsource-asm -ftrapuv -f[no]verbose-asm -g -g0
-inline-debug-info -map-opts -o<file> -pch
-pch-dir<dir> -print-multi-lib -S -use-asm
-use-msasm -use-pch<file>
Preprocessor Options
-A- -A<name>[<value(s)>] -C -D<name>[=<value>] -dD
-dM -dN -E -EP -H -I<dir> -idirafter<dir>
-imacros<file> -iprefix<prefix> -iquote<dir> -isys-
tem<dir> -iwithprefix<dir> -iwithprefixbefore<dir> -M
-MD -MF<file> -MG -MM -MMD -MP -MQ<target>
-MT<target> -no-gcc -nostdinc -P -U<name> -X
Component Control Options
-Qinstall<dir> -Qlocation,<tool>,<path> -Qop-
tion,<tool>,<optlist>
Language Options
-[no]align -ansi -[no-]c99 -export -export-dir <dir>
-fno-gnu-keywords -fno-implicit-inline-templates
-fno-implicit-templates -f[no-]non-lvalue-assign
-fno-operator-names -fpermissive -f[no-]rtti
-fshort-enums -fsyntax-only -ftemplate-depth-<n> -fun-
signed-bitfields -funsigned-char -Kc++ -malign-double
-[no]restrict -std=c99 -strict-ansi -Zp[n]
Compiler Diagnostics Options
-[no]traceback -w -w<n> -W[no-]abi -Wall -Wbrief
-Wcheck -W[no-]comment[s] -Wcontext-limit=<n>
-wd<L1>[,<L2>,...] -W[no-]deprecated
-we<L1>[,<L2>,...] -Werror -Winline -W[no-]main
-W[no-]missing-prototypes -wn<n> -Wp64
-W[no-]pointer-arith -wr<L1>[,<L2>,...]
-W[no-]return-type -W[no-]shadow -W[no-]uninitialized
-W[no-]unknown-pragmas -W[no-]unused-function
-ww<L1>[,<L2>,...]
Miscellaneous Options
-B<dir> -dryrun -fabi-version=<value> -f[no-]common
-f[no-]math-errno -fminshared -fno-builtin
-fno-builtin-<func> -fpack-struct -f[no-]pic
-f[no-]PIC -fr32 -freg-struct-return -fstack-secu-
rity-check -fvisibility=[extern | default | protected |
hidden | internal] -fvisibility-default=<file> -fvisi-
bility-extern=<file> -fvisibility-hidden=<file> -fvisi-
bility-internal=<file> -fvisibility-protected=<file>
-[no-]gcc-extern-inline -gcc-name=<dir> -gcc-ver-
sion=<nnn> -[no-]global-hoist -help -kernel -long_dou-
ble -mfixed-range=f12-f15,f32-f127 -[no-]multi-
byte-chars -nobss-init -reserve-kernel-regs -[no-]sox
-V -v --version -x<type>
Linking or Linker Options
-cxxlib-<mode> -dynamic-linker<filename> -dynamiclib
-i-dynamic -i-static -L<dir> -l<dir>
-mcmodel<mem_model> -m[no-]relax -no-cpprt -node-
faultlibs -nostartfiles -nostdlib -shared
-shared-libcxa -static -static-libcxa -T <file> -u
<symbol> -Wa<o1>[,<o2>,...] -Wl,<o1>[,<o2>,...]
-Wp,<o1>[,<o2>,...] -Xlinker<val>
Mac OS Options
-F<dir> -fpascal-strings -malign-mac68k -malign-natu-
ral -malign-power -mdynamic-no-pic
OPTION DESCRIPTIONS
Performance Options
The performance options act using general criteria to optimize
code. The optimizations listed in this section are available
for Intel architectures or are compatible with gcc compiler
options.
-ax<codes> (i32, i32em only) (not on M*X32)
Generates code for Intel(R) Core(TM) Duo processors,
Intel(R) Core(TM) Solo processors, Intel(R) Pentium(R) 4
processors with Streaming SIMD Extensions 3, and compat-
ible Intel processors with Streaming SIMD Extensions 3.
Generate code specialized for processor extensions spec-
ified by <codes> while also generating generic IA-32
code. <codes> includes one or more of the following
characters:
K -- Intel Pentium III processors and compatible Intel
processors
W -- Intel Pentium 4 processors and compatible Intel
processors
N -- Intel Pentium 4 processors and compatible Intel
processors. Enables new optimizations in addition to
Intel processor-specific optimizations.
B -- Intel Pentium M processors and compatible Intel
processors. Enables new optimizations in addition to
Intel processor-specific optimizations.
P -- Intel(R) Core(TM) Duo, Intel(R) Core(TM) Solo, and
Intel(R) Pentium(R) 4 Processors with Streaming SIMD
Extensions 3 (SSE3) instruction support. Enables new
optimizations in addition to Intel processor-specific
optimizations.
Note: The only -ax options available on Intel(R) EM64T-based
systems are -axW and -axP.
-f[no-]alias
Assume [do not assume] aliasing in the program (DEFAULT
= -falias).
-fast The -fast option maximizes speed across the entire pro-
gram. It sets command options that can improve run-time
performance, as follows:
i32, i32em: The -fast option turns on -O3, -ipo,
-static, -no-prec-div, and -xP. IA-32 programs compiled
with -fast will execute only on Intel(R) Pentium(R) 4
processors with Streaming SIMD Extensions 3 (SSE3).
Programs compiled with this option will detect non-com-
patible processors and generate an error message during
execution.
i64: The -fast option turns on -O3, -ipo, and -static.
M*X32: The -fast option turns on -O3, -ipo, -mdy-
namic-no-pic, and -no-prec-div.
-fdata-sections
Separate functions for the linker (COMDAT). Same as
-ffunction-sections.
-f[no-]exceptions
The -f[no-]exceptions option turns off exception han-
dling table generation, resulting in smaller code. Any
use of exception handling constructs - try blocks, throw
statements will produce an error. Exception specifica-
tions are parsed but ignored. A preprocessor symbol
__EXCEPTIONS is defined when this option is not used. It
is undefined when this option is present.
-f[no-]fnalias
Assume [do not assume, but assume aliasing across calls]
aliasing within functions (DEFAULT = -ffnalias).
-ffunction-sections
Separate functions for the linker (COMDAT). Same as
-fdata-sections.
-f[no-]inline
Enables [disables] inlining of functions declared with
the __inline keyword. Also enables inlining according to
the C++ language. Same as -Ob1.
-f[no-]inline-functions
Inline [do not inline] certain interprocedural optimiza-
tions for single file compilation. These optimizations
are a subset of full intra-file interprocedural opti-
mizations. Enables [does not enable] the compiler to
perform inline function expansion for calls to functions
defined within the current source file
-finline-limit=<n>
Lets you specify the maximum size of a function to be
inlined.
-fno-builtin-<func>
Disable the <func> intrinsic.
-f[no-]omit-frame-pointer (i32, i32em only)
The negative version is the same as -fp.
-fp (i32, i32em only)
Disable using EBP as general purpose register.
-[no-]fp-port (i32, i32em only)
Round floating-point results at assignments and casts
(some speed impact).
-fpstkchk (i32, i32em only)
Generate extra code after every function call to assure
that the FP stack is in the expected state. Generally,
when the FP stack overflows, a NaN value is put into FP
calculations, and the program's results differ. Unfortu-
nately, the overflow point can be far away from the
point of the actual bug. The -fpstkchk option places
code that would access violate immediately after an
incorrect call occurred, thus making it easier to locate
these issues.
-march=<cpu> (i32, i32em only)
Generate code exclusively for a given cpu, where <cpu>
is one of the following:
pentiumpro -- Intel Pentium Pro processors
pentiumii -- Intel Pentium II processors
pentiumiii -- Intel Pentium III processors
pentium2 -- Intel Pentium II processors
pentium3 -- Intel Pentium III processors
pentium4 -- Intel Pentium 4 processors
-mcpu=<cpu>
Optimize for a specific cpu, where <cpu> is one of the
following:
pentium -- (i32 only) Optimize for Intel Pentium proces-
sor.
pentiumpro -- (i32 only) Optimize for Intel Pentium Pro,
Intel Pentium II and Intel Pentium III processors.
pentium4 -- (i32 only; DEFAULT on IA-32) Optimize for
Intel Pentium 4 processors.
itanium -- (i64 only) Optimize for Intel Itanium proces-
sor
itanium2 -- (i64 only) Optimize for Intel Itanium 2 pro-
cessor.
itanium2-9000 -- (i64, L*X only) Optimize for Dual-Core
Intel(R) Itanium(R) 2 Processor 9000 Sequence proces-
sors.
-m[no-]ieee-fp
Same as -mp.
-mp Maintain floating-point precision (disables some opti-
mizations). The -mp option restricts optimization to
maintain declared precision and to ensure that float-
ing-point arithmetic conforms more closely to the ANSI
and IEEE standards. For most programs, specifying this
option adversely affects performance. If you are not
sure whether your application needs this option, try
compiling and running your program both with and without
it to evaluate the effects on both performance and pre-
cision.
-mp1 Improve floating-point precision. -mp1 disables fewer
optimizations and has less impact on performance than
-mp.
-msse (i32 only)
Generate code for Intel Pentium III and compatible Intel
processors.
-msse2 (i32 only)
Generate code for Intel Pentium 4 and compatible Intel
processors.
-msse3 (i32, i32em only)
Generate code for Intel Pentium 4 processors with SSE3
extensions.
-mtune=<cpu>
Optimize for a specific cpu, where <cpu> is one of the
following:
pentium -- (i32 only) Optimize for Intel Pentium proces-
sor.
pentiumpro -- (i32 only) Optimize for Intel Pentium Pro,
Intel Pentium II and Intel Pentium III processors.
pentium4 -- (i32 only; DEFAULT on IA-32) Optimize for
Intel Pentium 4 processors.
itanium -- (i64 only) Optimize for Intel Itanium proces-
sor
itanium2 -- (i64 only) Optimize for Intel Itanium 2 pro-
cessor.
itanium2-9000 -- (i64, L*X only) Optimize for Dual-Core
Intel(R) Itanium(R) 2 Processor 9000 Sequence proces-
sors.
-O0 Disable optimizations.
-O Same as -O2
-O1 Optimize to favor code size and code locality. Disables
loop unrolling. -O1 may improve performance for appli-
cations with very large code size, many branches, and
execution time not dominated by code within loops. In
most cases, -O2 is recommended over -O1.
i32: Disable intrinsics inlining to reduce code size.
i64: Disable software pipelining and global code
scheduling.
-O2 (DEFAULT)
Optimize for code speed. This is the generally recom-
mended optimization level.
i64: Turn software pipelining ON.
-O3 Enable -O2 optimizations and in addition, enable more
aggressive optimizations such as loop and memory access
transformation, and prefetching. The -O3 option opti-
mizes for maximum speed, but may not improve performance
for some programs. The -O3 optimizations may slow down
code in some cases compared to -O2 optimizations. Rec-
ommended for applications that have loops with heavy use
of floating point calculations and process large data
sets.
Turn on high-level optimizations. Enable -O2 plus more
aggressive optimizations, such as loop transformation.
i32, i32em: In conjunction with -ax{K|W|N|B|P} and
-x{K|W|N|B|P} options, this option causes the compiler
to perform more aggressive data dependency analysis than
for -O2. This may result in longer compilation times.
-Ob<n> Control inline expansion, where <n> is one of the fol-
lowing values:
0 -- Disables inlining.
1 -- (DEFAULT) Enables inlining of functions declared
with the __inline keyword. Also enables inlining accord-
ing to the C++ language.
2 -- Inlines any function, at the compiler's discretion.
Enables interprocedural optimizations and has the same
effect as -ip.
-Os Enable speed optimizations, but disable some optimiza-
tions that increase code size for small speed benefit.
-pc<n> (i32, i32em only)
Enable floating-point significand precision control.
Some floating-point algorithms are sensitive to the
accuracy of the significand, or fractional part of the
floating-point value. For example, iterative operations
like division and finding the square root can run faster
if you lower the precision with the -pc<n> option. Set
<n> to one of the following values to round the signifi-
cand to the indicated number of bits:
32: 24 bits (single precision) -- Caution: A change of
the default precision control or rounding mode (for
example, by using the -pc32 flag or by user interven-
tion) may affect the results returned by some of the
mathematical functions.
64: 53 bits (double precision)
80: 64 bits (extended precision) -- DEFAULT
-[no-]prec-div (i32, i32em only)
Improve precision of floating-point divides (some speed
impact). With some optimizations the Intel C++ Compiler
changes floating-point division computations into multi-
plication by the reciprocal of the denominator. For
example, A/B is computed as A x (1/B) to improve the
speed of the computation. However, for values of B
greater than 2126, the value of 1/B is "flushed"
(changed) to 0. When it is important to maintain the
value of 1/B, use -no-prec-div to disable the float-
ing-point division-to-multiplication optimization. The
result of -no-prec-div is more accurate, with some loss
of performance.
-[no-]prec-sqrt (i32, i32em only)
Determine if certain square root optimizations are
enabled.
-rcd (i32, i32em only)
Enable fast float-to-int conversions. The Intel compiler
uses the -rcd option to improve the performance of code
that requires floating-point-to-integer conversions. The
system default floating point rounding mode is
round-to-nearest. However, the C language requires
floating point values to be truncated when a conversion
to an integer is involved. To do this, the compiler must
change the rounding mode to truncation before each
floating-point-to-integer conversion and change it back
afterwards. The -rcd option disables the change to trun-
cation of the rounding mode for all floating point cal-
culations, including floating point-to-integer conver-
sions. Turning on this option can improve performance,
but floating point conversions to integer will not con-
form to C semantics.
-x<codes> (i32, i32em only) (not on M*X32)
Generates code for Intel(R) Core(TM) Duo processors,
Intel(R) Core(TM) Solo processors, Intel(R) Pentium(R) 4
processors with Streaming SIMD Extensions 3, and compat-
ible Intel processors with Streaming SIMD Extensions 3.
Generate specialized code to run exclusively on proces-
sors supporting the extensions indicated by <codes>.
<codes> includes one or more of the following charac-
ters:
K -- Intel Pentium III processors and compatible Intel
processors
W -- Intel Pentium 4 processors and compatible Intel
processors
N -- Intel Pentium 4 processors and compatible Intel
processors with Streaming SIMD Extensions 2 (SSE2)
instruction support. Enables new optimizations in addi-
tion to Intel processor-specific optimizations.
B -- Intel Pentium M processors and compatible Intel
processors. Enables new optimizations in addition to
Intel processor-specific optimizations.
P -- Intel(R) Core(TM) Duo, Intel(R) Core(TM) Solo, and
Intel(R) Pentium(R) 4 Processors with Streaming SIMD
Extensions 3 (SSE3) instruction support. Enables new
optimizations in addition to Intel processor-specific
optimizations.
Note: The only options available on Intel(R) EM64T-based
systems are -xW and -xP.
Note: If you specify more than one processor value, code
is generated for only the highest-performing processor
specified. For example, if you specify -xKW, only spe-
cialized code for the Intel Pentium 4 processor is gen-
erated.
Note: Programs compiled using option -xN, -xB, or -xP
will display a fatal run-time error if executed by an
unsupported processor. For more information, see the
Intel C++ Compiler User's Guide.
Note: The -x<codes> option is not supported on M*X32 for
this release. Compilations for M*X32 use the -xP option
values to generate code for Intel Pentium 4 Processors
with Streaming SIMD Extensions 3 (SSE3).
Advanced Performance Options
The advanced performance options allow fine tuning of compila-
tion or allow control over advanced features of the compiler.
-[no-]alias-args
Assume [do not assume] arguments may be aliased.
(DEFAULT = -no-alias-args).
-[no-]ansi-alias
The -[no-]ansi-alias option directs the compiler to
assume that the program adheres to the rules defined in
the ISO C Standard. If your program adheres to these
rules, then this option will allow the compiler to opti-
mize more aggressively. If it doesn't adhere to these
rules, then it can cause the compiler to generate incor-
rect code.
-auto-ilp32 (i32em, i64 only)
Specifies that the application should run within a
32-bit address space. Also tells the compiler to use
32-bit pointers whenever possible. To use this option,
you must specify -ipo.
Note: The -auto-ilp32 option applies to i64 and i32em,
but with i32em it has no effect unless option -xP or
option -axP is also specified. It does not apply to
i32.
-[no-]complex-limited-range
Tell the compiler to use the highest performance formu-
lations of complex arithmetic operations, which may not
produce acceptable results for input values near the top
or bottom of the legal range. Without this option, the
compiler uses a better formulation of complex arithmetic
operations, thus producing acceptable results for the
full range of input values, though at some loss in per-
formance.
-[no-]clomp-sharable-info (i32em, i64 only)
Reports variables that the compiler automatically makes
sharable for Cluster OpenMP*.
-[no-]clomp-sharable-propagation (i32em, i64 only)
Reports variables that need to be made sharable by the
user with Cluster OpenMP*.
-[no-]cluster-openmp (i32em, i64 only)
Compiles an OpenMP* program for execution on a cluster.
-[no-]cluster-openmp-profile (i32em, i64 only)
Compiles an OpenMP* program for execution on a cluster,
and links with a performance statistics library.
-fargument-[no-]alias
Same as -[no-]alias-args.
-fargument-noalias-global
Arguments do not alias each other and do not alias
global storage.
-[no-]fnsplit (i64 only)
Enable[disable] function splitting. Function splitting
is enabled by -prof-use in Phase 3 to improve code
locality by splitting routines into different sections:
one section to contain the cold or very infrequently
executed code, and one section to contain the rest of
the code (hot code).
You can use -[no-]fnsplit to disable function splitting
for the following reasons:
· Most importantly, to get improved debugging capa-
bility. In the debug symbol table, it is difficult
to represent a split routine, that is, a routine
with some of its code in the hot code section and
some of its code in the cold code section.
· The -no-fnsplit option disables the splitting
within a routine but enables function grouping, an
optimization in which entire routines are placed
either in the cold code section or the hot code
section. Function grouping does not degrade debug-
ging capability.
· When the profile data does not represent the actual
program behavior, that is, when the routine is
actually used frequently rather than infrequently.
-fp-model <name>
Enable <name> floating point model variation.
-ftls-model=<model>
Change thread-local storage model, where <model>
can be the following:
· global-dynamic
· local-dynamic
· initial-exec
· local-exec
-ftz (i64 only)
Flush denormal results to zero.
-funroll-loops
Unroll loops based on default heuristics.
-[no-]inline-factor=<n> Specifies the percentage
multiplier that should be applied to all inlining
options that define upper limits. The value <n> is
a positive integer specifying the percentage value.
The default value is 100 (a factor of 1).
-inline-forceinline
Specifies that an inline routine should be inlined
whenever the compiler can do so. (Default OFF)
-[no-]inline-max-per-compile=<n>
Specifies the maximum number of times inlining may
be applied to an entire compilation unit. The
value <n> is a positive integer that specifies the
number of times inlining may be applied. (Default
OFF)
-[no-]inline-max-per-routine=<n>
Specifies the maximum number of times the inliner
may inline into a particular routine. The value
<n> is a positive integer that specifies the maxi-
mum number of times the inliner may inline into a
particular routine. (Default OFF)
-[no-]inline-max-size=<n>
Specifies the lower limit for the size of what the
inliner considers to be a large routine. The value
<n> is a positive integer that specifies the mini-
mum size of what the inliner considers to be a
large routine. (Default OFF)
-[no-]inline-max-total-size=<n>
Specifies how much larger a routine can normally
grow when inline expansion is performed. The value
<n> is a positive integer that specifies the per-
mitted increase in the routine's size when inline
expansion is performed. (Default OFF)
-[no-]inline-min-size=<n>
Specifies the upper limit for the size of what the
inliner considers to be a small routine. The value
<n> is a positive integer that specifies the maxi-
mum size of what the inliner considers to be a
small routine. (Default OFF)
-ip Enable additional interprocedural optimizations for
single file compilation. These optimizations are a
subset of full intra-file interprocedural optimiza-
tions.
-IPF-flt-eval-method0 (i64 only)
Direct the compiler to evaluate the expressions
involving floating-point operands in the precision
indicated by the variable types declared in the
program.
-[no-]IPF-fltacc (i64 only)
Enable [disable] optimizations that affect floating
point accuracy. By default (-IPF-fltacc-) the
compiler may apply optimizations that reduce float-
ing-point accuracy. You may use -IPF-fltacc or -mp
to improve floating-point accuracy, but at the cost
of disabling some optimizations.
-[no-]IPF-fma (i64 only)
Enable [disable] the combining of floating point
multiplies and add/subtract operations. -IPF-fma[-]
enables [disables] the contraction of float-
ing-point multiply and add/subtract operations into
a single operation. Unless -mp is specified, the
compiler contracts these operations whenever possi-
ble. The -mp option disables the contractions.
-IPF-fma and -IPF-fma- can be used to override the
default compiler behavior.
-[no-]IPF_fp_relaxed (i64 only)
Enable [disable] use of faster but slightly less
accurate code sequences for math functions, such as
divide and square root.
-IPF-fp-speculation{fast|safe|strict|off} (i64 only)
Enable floating point speculations with the follow-
ing conditions:
fast -- Speculate floating point operations
safe -- Speculate only when safe
strict -- Same as off
off -- Disables speculation of floating-point oper-
ations
-ip-no-inlining
Disable inlining that would result from the -ip
interprocedural optimization, but has no effect on
other interprocedural optimizations.
-ip-no-pinlining (i32, i32em only)
Disable partial inlining (requires -ip or -ipo)
-ipo[value] Enables multifile IP optimizations (between files).
When you specify this option, the compiler performs
inline function expansion for calls to functions
defined in separate files.
The [value] argument is an optional integer that
specifies the number of object files the compiler
should create. Any integer greater than or equal
to 0 is valid.
If [value] is 0, the compiler decides whether to
create one or more object files based on an esti-
mate of the size of the object file. It generates
one object file for small applications, and two or
more object files for large applications.
If [value] is positive, the compiler generates
[value] object files, unless [value] exceeds the
number of source files (m), in which case the com-
piler generates only m object files.
If you do not specify [value], the default is 1.
-ipo-c Generate a multi-file object file (ipo-out.o) that
can be used in further link steps.
-ipo-S Generate a multi-file assembly file (ipo-out.s)
that can be used in further link steps.
-ipo-separate
Creates one object file for every source file. This
option overrides -ipo[value].
-ivdep-parallel (i64 only)
Indicate there is absolutely no loop-carried memory
dependency in any loop where IVDEP directive is
specified. This technique is useful for some sparse
matrix applications.
-mno-serialize-volatile (i64 only)
Memory access ordering for volatile data object
references may be suppressed.
-mserialize-volatile (i64 only)
Enable strict memory access ordering for volatile
data object references.
-openmp Enable the parallelizer to generate multi-threaded
code based on the OpenMP* directives. The code can
be executed in parallel on both uniprocessor and
multiprocessor systems. The -openmp option works
with both -O0 (no optimization) and any optimiza-
tion level of -O1, -O2 (default) and -O3. Specify-
ing -O0 with -openmp helps to debug OpenMP applica-
tions.
-openmp-profile
Enables analysis of OpenMP* applications with
Intel(R) Thread Profiler, which is required to use
this option.
-openmp-report[<n>]
Control the OpenMP parallelizer's level of diagnos-
tic messages, where <n> is one of the following:
0 -- no diagnostic information is displayed.
1 -- Display diagnostics indicating loops, regions,
and sections successfully parallelized. (DEFAULT)
2 -- same as -openmp-report1 plus diagnostics indi-
cating MASTER constructs, SINGLE constructs, CRITI-
CAL constructs, ORDERED constructs, ATOMIC direc-
tives, etc. successfully handled.
-openmp-stubs
Enable the user to compile OpenMP programs in
sequential mode. The openmp directives are ignored
and a stub OpenMP library is linked (sequential).
-opt-mem-bandwidth<n> (i64, L*X only)
Enables or disables performance tuning and heuris-
tics that control memory bandwidth use among pro-
cessors. It allows the compiler to be less aggres-
sive with optimizations that might consume more
bandwidth, so that the bandwidth can be well-shared
among multiple processors for a parallel program.
For values of <n> greater than 0, the option tells
the compiler to enable a set of performance tuning
and heuristics in compiler optimizations such as
prefetching, privatization, aggressive code motion,
and so forth, for reducing memory bandwidth pres-
sure and balancing memory bandwidth traffic among
threads. The <n> value is the level of optimizing
for memory bandwidth usage. You can specify one of
the following values for <n>:
0 -- Disables a set of performance tuning and
heuristics in compiler optimizations for parallel
code. This is the default for serial code.
1 -- Enables a set of performance tuning and
heuristics in compiler optimizations for multi-
threaded code generated by the compiler. This is
the default if compiler option -parallel or -openmp
is specified, or Cluster OpenMP option -clus-
ter-openmp is specified (see the Cluster OpenMP
documentation).
2 -- Enables a set of performance tuning and
heuristics in compiler optimizations for parallel
code such as Windows Threads, pthreads, and MPI
code, besides multithreaded code generated by the
compiler.
-opt-report Generate an optimization report and direct it to
stderr.
DEFAULT: The compiler does not generate optimiza-
tion reports.
-opt-report-file<file>
Specify the filename for the generated report
-opt-report-help
List the logical names of optimizers available for
report generation.
-opt-report-level[<level>]
Specify the level of report verbosity, where
<level> is one of the following:
min -- The min argument provides the minimal sum-
mary (DEFAULT)
med -- The med argument produces an intermedi-
ate-level report.
max -- The max argument produces the full report.
-opt-report-phase<name>
Specify the optimizer phase against which reports
are generated. The compiler generates reports for
the optimizer you specify in the <name>. This
option can be used multiple times on the same com-
mand line to generate reports for multiple optimiz-
ers. Currently, the following optimizer reports are
supported:
ipo -- Interprocedural Optimizer
hlo -- High Level Optimizer
ilo -- Intermediate Language Scalar Optimizer
ecg -- Code Generator
omp -- OpenMP
all -- All phases
When one of the above logical names for optimizers
is specified for <name>, all reports from that
optimizer are generated.
-opt-report-routine<substring>
Generate reports from all routines with names con-
taining <substring> as part of their name. If <sub-
string> is not specified, reports from all routines
are generated.
DEFAULT: The compiler generates reports for all
routines.
-p Compile and link for function profiling with Linux
gprof* tool. Same as -qp.
-parallel Enable the auto-parallelizer to generate
multi-threaded code for loops that can be safely
executed in parallel. The -parallel option enables
the auto-parallelizer if either the -O2 or -O3
optimization option is also on (the default is
-O2).
-par-report[<n>]
Control the level of auto-parallelizer diagnostic
messages, where <n> is one of the following:
0 -- no diagnostic information is displayed.
1 -- indicates loops successfully auto-parallelized
(DEFAULT). Issues a "LOOP AUTO-PARALLELIZED" mes-
sage for parallel loops.
2 -- indicates successfully auto-parallelized loops
as well as unsuccessful loops.
3 -- same as 2 plus additional information about
any proven or assumed dependencies inhibiting
auto-parallelization (reasons for not paralleliz-
ing).
-par-threshold[<n>]
Set a threshold for the auto-parallelization of
loops based on the probability of profitable
execution of the loop in parallel. This option is
used for loops whose computation work volume cannot
be determined at compile-time. The threshold is
usually relevant when the loop trip count is
unknown at compile-time.
<n>=0-100. (DEFAULT: <n>=75)
The compiler applies a heuristic that tries to bal-
ance the overhead of creating multiple threads ver-
sus the amount of work available to be shared
amongst the threads.
-[no-]prefetch (i64 only)
Enables [disables] the insertion of software
prefetching by the compiler. Default is -prefetch.
-prof-dir <dir>
Specify directory <dir> for profiling output files
(*.dyn and *.dpi). Use the -prof-dir option with
prof-gen as recommended for most programs, espe-
cially if the application includes the source files
located in multiple directories. -prof-dir ensures
that the profile information is generated in one
consistent place.
-prof-file <file>
Specify file name <file> for profiling summary file
-prof_gen[x]
Instruct the compiler to produce instrumented code
in your object files in preparation for instru-
mented execution. With the x qualifier, extra
information is gathered. This option is used in
Phase 1 of PGO to instruct the compiler to produce
instrumented code in your object files in prepara-
tion for instrumented execution. Parallel make is
automatically supported for -prof-genx compila-
tions.
-prof-gen-sampling
Prepare code for use with the profrun sample gath-
ering tool.
-prof_use Instruct the compiler to produce a profile-opti-
mized executable and merge available dynamic infor-
mation (.dyn) files into a pgopti.dpi file. Use the
-prof-use option in Phase 3 of PGO.
-qp Compile and link for function profiling with Linux
gprof* tool. Same as -p.
-ssp (i32 only)
Enable software-based speculative pre-computation.
-tcheck The -tcheck compiler option enables analysis of
threaded applications with Intel(R) Thread Checker,
which is required to use this option.
-unroll<n> (i32, i32em only)
Set maximum number of times to unroll loops. This
applies only to loops that the compiler determines
should be unrolled. Omit n to let the compiler
decide whether to perform unrolling or not. Use n=0
to disable loop unrolling.
-unroll0 (i64 only)
Disable loop unrolling. For i64: the only allowed
value is 0.
-vec-report[<n>] (i32, i32em only)
Control the vectorizer's level of diagnostic mes-
sages, where <n> is one of the following:
0 -- No diagnostic information
1 -- Indicate vectorized loops (DEFAULT)
2 -- Indicate vectorized/non-vectorized loops
3 -- Indicate vectorized/non-vectorized loops and
prohibiting data dependence information
4 -- Indicate non-vectorized loops
5 -- Indicate non-vectorized loops and prohibiting
data dependence information
If you use -c, -ipo with -vec-report{n} option or
-c, -x{K|W|N|B|P} or -ax{K|W|N|B|P} with
-vec-report[<n>], the compiler issues a warning and
no report is generated.
Output, Debug, and PCH Options
The output, debug, and PCH options provide control over com-
piler output, setup for debugging, and use of the precompiled
header features of the compiler.
-c Compile to object (.o) only, do not link.
-create-pch <filename>
Manual creation of precompiled header <filename>. Use
the -create-pch <filename> option if you want the com-
piler to create a PCH file called <filename>. The file-
name parameter must be specified. The filename parame-
ter can be a full path name. The full path to filename
must exist. The .pchi extension is not automatically
appended to filename. This option cannot be used in the
same compilation as -use-pch filename. The -create-pch
filename option is supported for single source file
compilations only.
-[no-]debug[keyword]
Enable debug information and control output of enhanced
debug information. The supported [keywords] are
extended, [no]variable-locations, [no]semantic-stepping,
[no-]expr-source-pos, and [no]inline_debug_info}. The
debug switches control emission of enhanced debug infor-
mation. They must be used in conjunction with the basic
-g switches that request debug information.
extended -- Turns on the -debug options;
· -debug [no-]expr-source-pos,
· -debug [no]variable-locations,
· -debug [no]semantic-stepping, and
· -debug [no]inline_debug_info.
[no-]expr-source-pos -- Determines whether source
position information at the expression level of
granularity is produced.
[no]variable-locations -- Determines whether
enhanced debug information useful in finding scalar
local variables is produced.
[no]semantic-stepping -- Determines whether
enhanced debug information useful for breakpoints
and stepping is produced.
[no]inline_debug_info -- Determines whether
enhanced debug information is produced for inlined
code.
-fcode-asm Produce assembly file with optional code annota-
tions.
-fsource-asm
Produce assembly file with optional code annota-
tions.
-ftrapuv Initializes stack local variables to an unusual
value to help error detection.
-f[no]verbose-asm
Produce assembly file with compiler comments
(DEFAULT).
-g Produce symbolic debug information in object file.
The compiler does not support the generation of
debugging information in assemblable files. If you
specify the -g option, the resulting object file
will contain debugging information, but the assem-
blable file will not. The -g option changes the
default optimization from -O2 to -O0.
If you specify -g with -O1, -O2, or -O3, then -fp
is disabled and allows the compiler to use the EBP
register as a general-purpose register in optimiza-
tions. However, most debuggers expect EBP to be
used as a stack frame pointer, and cannot produce a
stack backtrace unless this is so. Using the -fp
option can result in slightly less efficient code.
i32 only: Specifying the -g or -O0 option automati-
cally enables the -fp option.
-g0 Disable generation of symbolic debug information.
-inline-debug-info
Preserve the source position of inlined code
instead of assigning the call-site source position
to inlined code.
-map-opts (not on M*X32)
Enable option mapping tool.
-o<file> This option specifies the name of an output file as
follows:
· If the -c option is specified, it specifies the
name of the generated object file.
· If the -S option is specified, it specifies the
name of the generated assembly listing file.
· If the -P option is specified, it specifies the
name of the generated preprocessor file.
Otherwise, it specifies the name of the executable
file.
-pch Automatic processing for precompiled headers.
Direct the compiler to use appropriate PCH files.
If none are available, they are created as source-
file.pchi. This option supports multiple source
files.
Note: The -pch option uses PCH files created from
other sources if the headers files are the same.
For example, if you compile source1.cpp using -pch,
then source1.pchi is created. If you then compile
source2.cpp using -pch, the compiler will use
source1.pchi if it detects the same headers.
-pch-dir <dirname>
Directs the compiler to find and/or create a file
for pre-compiled headers in dirname. Use the
-pch-dir <dirname> option to specify the path
(dirname) to the PCH file. You can use this option
with -pch, -create-pch filename, and -use-pch file-
name.
-print-multi-lib
Print information about libraries being used.
-S Compile to an assemblable file (.s), then stop the
compilation.
-use-asm Produce objects through the assembler.
Note: GNU inline assembler (asm) code and
Microsoft inline assembler (msasm) code cannot be
used together in the same translation unit.
-use-msasm (i32, i32em only)
Support Microsoft* style assembly language inser-
tion using MASM style syntax and, if requested,
output assembly in MASM format.
Note: GNU inline assembler (asm) code and
Microsoft inline assembler (msasm) code cannot be
used together in the same translation unit.
-use-pch <filename>
Manual use of precompiled header (filename.pchi).
This option directs the compiler to use the PCH
file specified by filename. It cannot be used in
the same compilation as -create-pch <filename>. The
-use-pch <filename> option supports full path names
and supports multiple source files when all source
files use the same .pchi file.
Preprocessor Options
The preprocessor options listed here control preprocessing
operations for the compiler.
-A- Remove all predefined macros. Causes all predefined
macros and assertions to be inactive.
-A<name>[<value(s)>]
Associate a symbol <name> with the specified sequence of
<value(s)>. Equivalent to an #assert preprocessing
directive.
-C Preserve comments in preprocessed source output. Com-
ments following preprocessing directives are not pre-
served.
-D<name>[=<value>]
Define the macro <name> and associate it with the speci-
fied <value>. Equivalent to a #define preprocessing
directive.
DEFAULT: -D<name> defines the macro <name> with a
<value> of 1.
-dD Same as -dM, but outputs #define directives in prepro-
cessed source.
-dM Output macro definitions in effect after preprocessing
(use with -E).
-dN Same as -dD, but #define directives contain only macro
names.
-E Direct the preprocessor to expand your source module and
write the result to standard output. The preprocessed
source contains #line directives, which the compiler
uses to determine the source file and line number.
-EP Direct the preprocessor to expand your source module and
write the result to standard output. Does not include
#line directives in the output. -EP is equivalent to -E
-P.
-H Print "include" file order and continue compilation.
-I<dir>
Add directory <dir> to include file search path. For
multiple search directories, multiple I<dir> commands
must be used. The compiler searches directories for
include files in the following order: 1. Directory of
the source file that contains the include. 2. Directo-
ries specified by the -I option.
-idirafter<dir>
Add directory <dir> to the second include file search
path (after -I).
-imacros<file>
Treat <file> as an #include file, but throw away all
preprocessing while the macros that are defined remain
defined.
-iprefix<prefix>
Use <prefix> with -iwithprefix as a prefix.
-iquote<dir>
Add <dir> to the front of the include file search path
for files included with quotes but not brackets.
(DEFAULT = OFF)
-isystem<dir>
Add directory <dir> to the start of the system include
path.
-iwithprefix<dir>
Append <dir> to the prefix passed in by -iprefix and put
it on the include search path at the end of the include
directories.
-iwithprefixbefore<dir>
Similar to -iwithprefix except the include directory is
placed in the same place as the -I command line include
directories.
-M Generate makefile dependency lines for each source file,
based on the #include lines found in the source file.
-MD Preprocess and compile. Generate output file (.d exten-
sion) containing dependency information.
-MF<file>
Generate makefile dependency information in <file>. Must
specify -M or -MM.
-MG Similar to -M, but treats missing header files as gener-
ated files.
-MM Similar to -M, but does not include system header files.
-MMD Similar to -MD, but does not include system header
files.
-MP Add a phony target for each dependency.
-MQ<target>
Same as -MT, but quotes special Make characters.
-MT<target>
Change the default target rule for dependency genera-
tion.
-no-gcc
Do not predefine the __GNUC__, __GNUC_MINOR__, and
__GNUC_PATCHLEVEL__ macros.
-nostdinc
Same as -X.
-P Direct the preprocessor to expand your source module and
store the result in a .i file in the current directory.
Unlike the -E option, the output from -P does not
include #line number directives. By default, the prepro-
cessor creates the name of the output file using the
prefix of the source file name with a .i extension.
Caution: When you use the -P option, any existing files
with the same name and extension are overwritten.
-U<name>
Remove predefined macro. Equivalent to a #undef prepro-
cessing directive.
-X Remove standard directories from include file search
path. You can use the -X option with the -I option to
prevent the compiler from searching the default path for
include files and direct it to use an alternate path.
Component Control Options
You can direct the compiler to specify alternate tools for pre-
processing, compilation, assembly, and linking. Further, you
can invoke options specific to your alternate tools on the com-
mand line. These are the component control options.
-Qinstall <dir>
Set <dir> as the root of the compiler installation.
-Qlocation,<tool>,<path>
Set <path> as the location of the tool specified by
<tool>. <tool> may be cpp, c, asm, or ld. <path> is the
complete path to the tool. For example:
-Qlocation,gas,<path> Specifies the GNU assembler.
-Qlocation,gld,<path> Specifies the GNU linker.
-Qoption,<tool>,<optlist>
Pass options <optlist> to the tool specified by <tool>.
<tool> may be cpp, c, asm, or ld. The <optlist> argu-
ment indicates one or more valid argument strings for
the designated program. If the argument is a com-
mand-line option, you must include the hyphen. If the
argument contains a space or tab character, you must
enclose the entire argument in quotation characters
(""). You must separate multiple arguments with commas.
Language Options
The language options define parameters and standards for the
compiler with reference to the C/C++ source files.
-[no]align (i32, i32em only)
Analyze and reorder memory layout for variables and
arrays.
-ansi Support all ANSI standard C programs, equivalent to the
-ansi option of gcc.
-[no-]c99
Enable [disable] C99 support for C programs.
-export
Enable recognition of exported templates. Supported in
C++ mode only.
-export-dir <dir>
Specifies a directory name for the exported template
search path.
-fno-gnu-keywords
Do not recognize 'typeof' as a keyword.
-fno-implicit-inline-templates
Do not emit code for implicit instantiations of inline
templates.
-fno-implicit-templates
Never emit code for non-inline templates which are
instantiated implicitly (i.e. by use); only emit code
for explicit instantiations.
-f[no-]non-lvalue-assign
Allow [disallow] casts and conditional expressions to be
used as lvalues. (DEFAULT = allow)
-fno-operator-names
Disable support for operator name keywords.
-fpermissive
Allow for non-conformant code.
-f[no-]rtti
Enable [disable] RTTI support.
-fshort-enums
Allocate as many bytes as needed for enumerated types.
-fsyntax-only
Same as -syntax.
-ftemplate-depth-<n>
Control the depth to which recursive templates are
expanded.
-funsigned-bitfields
Change default bitfield type to unsigned.
-funsigned-char
Change default char type to unsigned.
-Kc++ Compile all source or unrecognized file types as C++
source files.
-malign-double (i32, i32em only)
Same as -align.
-[no]restrict
Enable [disable] the "restrict" keyword for disambiguat-
ing pointers.
-std=c99
Enable C99 support for C programs
-strict-ansi
Select strict ANSI C/C++ conformance dialect
-Zp[n] Specify alignment constraint for structure and union
types, where n is one of the following: 1,2,4,8,16.
Compiler Diagnostics Options
The compiler diagnostics options define and control aspects of
the compilation associated with diagnostics.
-[no]traceback
Tells the compiler to generate [not generate] extra
information in the object file to allow the display of
source file traceback information at run time when a
severe error occurs. This is intended for use with C
code that is to be linked into a Fortran program.
-w Disable all warnings. Displays error messages only.
-w<n> Control diagnostics, where <n> is one of the following:
0 -- Display errors (same as -w)
1 -- Display warnings and errors (DEFAULT)
2 -- Display remarks, warnings, and errors
-W[no-]abi
Warn [do not warn] if generated code is not C++ ABI com-
pliant (Default = -Wno-abi).
-Wall Enable all warnings.
-Wbrief
Print brief one-line diagnostics. When enabled, the
original source line is not displayed and the error mes-
sage text is not wrapped when too long to fit on a sin-
gle line.
-Wcheck
Enable more strict diagnostics. Performs compile-time
code checking for code that exhibits non-portable behav-
ior, represents a possible unintended code sequence, or
possibly affects operation of the program because of a
quiet change in the ANSI C Standard.
-W[no-]comment[s]
Warn when /* appears in the middle of a /* */ comment.
-Wcontext-limit=<n>
Set maximum number of template instantiation contexts
shown in diagnostic.
-wd<L1>[,<L2>,...<LN>]
Disable diagnostics L1 through LN.
-W[no-]deprecated
Print warnings related to deprecated features.
-we<L1>[,<L2>,...<LN>]
Change severity of diagnostics L1 through LN to error.
-Werror
Force warnings to be reported as errors.
-Winline
Enable inline diagnostics.
-W[no-]main
Warn if return type of main is not expected.
-W[no-]missing-prototypes
Warn for missing prototypes.
-wn<n> Print a maximum of <n> errors displayed before the com-
piler aborts. By default, if more than 100 errors are
displayed, compilation aborts. Remarks and warnings do
not count towards this limit.
-Wp64 Print diagnostics for 64-bit porting.
-W[no-]pointer-arith
Warn for questionable pointer arithmetic.
-wr<L1>[,<L2>,...<LN>]
Change severity of diagnostics L1 through LN to remark.
-W[no-]return-type
Warn when a function uses the default int return type
and warn when a return statement is used in a void func-
tion.
-W[no-]shadow
Warn if a variable declaration hides a previous variable
declaration.
-W[no-]uninitialized
Warn if a variable is used before being initialized.
-W[no-]unknown-pragmas
Warn if an unknown #pragma directive is used (DEFAULT).
-W[no-]unused-function
Warn if declared function is not used.
-ww<L1>[,<L2>,...<LN>]
Change severity of diagnostics L1 through LN to warning.
Miscellaneous Options
The miscellaneous options cover a variety of unrelated tasks
related to the compiler.
-B<dir>
Specifies the directory (dir) that can be used to find
libraries, headers, and executables for the compiler
itself.
-dryrun
Show driver tool commands but do not execute tools.
-fabi-version=<value>
Instructs the compiler to select a specific ABI imple-
mentation, where <value> is the ABI implementation. Pos-
sible values are:.
0 -- Requests all the latest ABI fixes. Default if gcc
version 3.2 is installed.
1 -- Requests the ABI used in gcc 3.3. Default if gcc
version 3.3 is installed.
2 -- Requests the ABI used in gcc 3.4 and higher.
Default if gcc version 3.4 or higher is installed.
-f[no-]common
Enables the compiler to treat common variables as if
they were defined, allowing the use of gprel addressing
of common data variables.
-f[no-]math-errno
Set ERRNO after calling standard math library functions.
-fminshared
Compilation is for the main executable. Absolute
addressing can be used and non-position independent code
generated for symbols that are at least protected.
-fno-builtin
Disable inline expansion of intrinsic functions.
-fno-builtin-<func>
Disable the <func> intrinsic.
-fpack-struct
Pack structure members together.
-f[no-]pic, -f[no-]PIC
i32: This option generates position independent code.
By default this option is OFF.
i64: This option generates code allowing full symbol
preemption. By default this option is OFF.
-fr32 (i64 only)
Disable use of high floating point registers. Use only
lower 32 floating-point registers.
-freg-struct-return
Return struct and union values in registers when possi-
ble.
-fstack-security-check (i32, i32em only)
Enable overflow security checks.
-fvisibility=[extern|default|protected|hidden|internal]
Global symbols (data and functions) will get the visi-
bility attribute given by default. Symbol visibility
attributes explicitly set in the source code or using
the symbol visibility attribute file options will over-
ride the -fvisibility setting.
-fvisibility-default=<file>
Space separated symbols listed in the <file> argument
will get visibility set to default.
-fvisibility-extern=<file>
Space separated symbols listed in the <file> argument
will get visibility set to extern.
-fvisibility-hidden=<file>
Space separated symbols listed in the <file> argument
will get visibility set to hidden.
-fvisibility-internal=<file> (not on M*X32)
Space separated symbols listed in the <file> argument
will get visibility set to internal.
-fvisibility-protected=<file> (not on M*X32)
Space separated symbols listed in the <file> argument
will get visibility set to protected.
-[no-]gcc-extern-inline
The -gcc-extern-inline flag, by default, lays down a
body for a function declared to be extern inline. The
gcc compiler, however, never lays down a body for a
function declared to be extern inline. Instead, gcc
treats the function as if it were declared extern but
with no definition in the compilation unit.
No body is created unless the function cannot be inlined
for some reason (for example, its address might be
taken). The body laid down for a function because of
this flag will always be weak so a non-weak definition
elsewhere in the compilation will be used instead. If
you want the C99 behavior rather than the now default
(more) gcc like behavior, use the -no-gcc-extern-inline
flag. This flag is on (i.e. -gcc-extern-inline) by
default.
-gcc-name=<dir>
Use this option to specify the location of g++ when com-
piler cannot locate gcc C++ libraries. For use with
-cxxlib-<mode> configuration. The <dir> argument is the
full path location of g++. Use this option when refer-
encing a non-standard gcc installation.
-gcc-version=<nnn>
This option provides compatible behavior with gcc, where
<nnn> indicates the gcc version. The required values
for <nnn> are:
not set -- if gcc version is older than 3.2
320 -- if gcc version is 3.2
330 -- if gcc version is 3.3
340 -- if gcc version is 3.4
400 -- if gcc version is 4.0
410 -- if gcc version is 4.1
Note: The <nnn> version number follows a format where
the first number represents the major version, the sec-
ond number represents the minor version, and the third
number is normally zero. For example, the 3.3.1 gcc
version is represented as 330.
-[no-]global-hoist
Enables [disables] hoisting and speculative loads of
global variables.
-help Print list of compiler options.
-kernel (i64 only)
Generates code for inclusion in the kernel. Prevents
generation of speculation as support may not be avail-
able when code runs. Suppresses software pipelining.
-long_double (i32, i32em only)
Enable 80-bit 'long double'. The -long_double option is
ON by default (80-bit) for L*X and M*X32.
-mfixed-range=<range> (i64 only)
Reserves certain registers (<range>=f12-f15, f32-f127)
for use by the kernel.
-[no-]multibyte-chars
Provide support for multi-byte characters.
-nobss-init
Place variables that are initialized with zeroes in the
DATA section instead of the BSS section.
-reserve-kernel-regs (i64 only)
Reserves registers f12-f15 and f32-f127 for use by the
kernel. These will not be used by the compiler.
-[no-]sox
Enable (DEFAULT) [disable] saving of compiler options
and version in the executable.
-V Display compiler version information.
-v Show driver tool commands and execute tools.
--version
Display GCC style version information. Note that two
'-'s are required.
-x <type>
All source files found subsequent to -x <type> will be
recognized as one of the following types:
c -- C source file
c++ -- C++ source file
c-header -- C header file
cpp-output -- C pre-processed file
c++-cpp-output -- C++ pre-processed file
assembler -- Assembly file
assembler-with-cpp -- Assembly file that needs to be
preprocessed
none -- Disable recognition, and revert to file exten-
sion
Linking or Linker Options
The linking/linker options group all link-related options
together.
-cxxlib-<mode>
Tells the compiler to link using certain C++ runtime
libraries. You can specify one of the following values
for <mode>:
gcc[=<dir>] -- Link using the C++ run-time libraries
provided with the gcc compiler. The <dir>parameter is
an optional top-level location for the gcc binaries and
libraries.
icc -- Link using the C++ run-time libraries provided by
Intel.
-dynamic-linker<filename>
Select a dynamic linker (filename) other than the
default.
-dynamiclib (i32, M*X32 only)
Invokes the libtool command to generate dynamic
libraries.
-i-dynamic
Link Intel provided libraries dynamically.
-i-static
Links Intel-provided libraries statically.
-L<dir> or -l<dir>
Instruct the linker to search for a specified library
<dir> when linking. Because the linker searches and
processes libraries and object files in the order they
are specified, specify this option following the last
applicable object file.
-mcmodel=<mem_model> (i32, L*X only)
Tells the compiler to use a specific memory model to
generate code and store data. Default is
-mcmodel=small.
-m[no-]relax (i64 only)
Pass [do not pass] -relax to the linker. (DEFAULT =
-mno-relax)
-no-cpprt
Do not link in C++ runtime libraries.
-nodefaultlibs
Do not use standard libraries when linking.
-nostartfiles
Do not use standard startup files when linking.
-nostdlib
Do not use standard libraries and startup files when
linking.
-shared (not on M*X32)
Produce a shared object.
-shared-libcxa
Link Intel libcxa C++ library dynamically, overriding
the default behavior when -static is used. This option
has the opposite effect of -static-libcxa. When this
option is used, the Intel-provided libcxa C++ library is
linked in dynamically, allowing the user to override the
static linking behavior when the -static option is used.
-static (not on M*X32)
Prevent linking with shared libraries. Causes the exe-
cutable to link all libraries statically, as opposed to
dynamically.
-static-libcxa
Link Intel libcxa C++ library statically. By default,
the Intel-provided libcxa C++ library is linked in
dynamically. Use -static-libcxa on the command line to
link libcxa statically, while still allowing the stan-
dard libraries to be linked in by the default behavior.
-T <file>
Direct linker to read link commands from <file>.
-u <symbol>
Pretend the <symbol> is undefined.
-Wa<o1>[,<o2>,...]
-Wl,<o1>[,<o2>,...]
-Wl,<o1>[,<o2>,...]
Pass options o1, o2, etc. to the linker for processing.
-Xlinker <val> (i32, i32em only)
Pass <val> directly to the linker for processing.
Mac OS Options
The Mac OS options provide specific capabilities that apply
only to the Intel C++ compiler for the Mac OS. Most other i32
C++ compiler options (except those identified with a (not on
M*X32) notation) also apply to the Mac OS.
-F<dir> (M*X32 only)
Add a framework directory to the head of an include file
search path.
-fpascal-strings (M*X32 only)
Allow for Pascal-style string literals.
-malign-mac68k (M*X32 only)
Aligns structure fields on 2-byte boundaries (m68k com-
patible).
-malign-natural (M*X32 only)
Aligns larger types on natural size-based boundaries
(overrides ABI).
-malign-power (M*X32 only)
Aligns based on ABI-specified alignment rules (default
for M*X32 only).
-mdynamic-no-pic (M*X32 only)
Code is not relocatable, but external references are
relocatable.
Optimization Levels
The Intel C++ Compiler applies the following optimizations when
you invoke the -O1, -O2, or -O3 options:
· Constant propagation
· Copy propagation
· Dead-code elimination
· Global register allocation
· Instruction scheduling
· Loop unrolling (-O2, -O3 only)
· Loop-invariant code movement
· Partial redundancy elimination
· Strength reduction/induction variable simplification
· Variable renaming
· Exception handling optimizations
· Tail recursions
· Peephole optimizations
· Structure assignment lowering and optimizations
· Dead store elimination
· Loop-invariant code motion.
Depending on the Intel architecture, optimization options can
have different effects. To specify optimizations for your tar-
get architecture, refer to the -O[0|1|2|3], -fast, -ax<code>,
-x<code>, and related options.
Optimizing Exclusively for Specific Processors (i32, i32em only)
(not on M*X32)
The -x{K|W|N|B|P} options target your program to run on a spe-
cific Intel processor. The resulting code might contain uncon-
ditional use of features that are not supported on other pro-
cessors. If these options are used on a non-compatible proces-
sor, the program might fail with an illegal instruction excep-
tion, or it might display other unexpected behavior. Do not
specify this option if the program will be executed on x86 pro-
cessors not provided by Intel Corporation. For more informa-
tion, see the Intel C++ Compiler User's Guide.
Note: The -x<codes> option is not supported on M*X32 for this
release. Compilations for M*X32 use the -xP option values to
generate code for Intel Pentium 4 Processors with Streaming
SIMD Extensions 3 (SSE3).
Automatic Processor-specific Optimization (i32, i32em only) (not on
M*X32)
The -ax{K|W|N|B|P} options direct the compiler to find opportu-
nities to generate separate versions of functions that use
instructions supported on the specified processors. If the com-
piler finds such an opportunity, it first checks whether gener-
ating a processor-specific version of a function is likely to
result in a performance gain. If so, the compiler generates
both a processor-specific version of a function and a generic
version of the function. The generic version will run on any
IA-32 processor.
At run time, one of the versions is chosen to execute, depend-
ing on the current processor. In this way, the program can ben-
efit from performance gains on more advanced processors, while
still working properly on older processors.
The disadvantages of using -ax{K|W|N|B|P} are:
· The size of the compiled binary increases because it con-
tains both a processor-specific version of some of the code
and a generic version of the code.
· Performance is affected by the run-time checks to determine
which code to run.
Interprocedural Optimizations (IPO)
Use -ip and -ipo[value] to enable interprocedural optimizations
(IPO), which allow the compiler to analyze your code to deter-
mine where to apply the following optimizations: inline func-
tion expansion, interprocedural constant propagation, monitor-
ing module-level static variables, dead code elimination, prop-
agation of function characteristics, and multifile optimiza-
tion. For IA-32, IPO also passes arguments in registers.
Inline function expansion is one of the main optimizations per-
formed by the interprocedural optimizer. For function calls
that the compiler believes are frequently executed, the com-
piler might decide to replace the instructions of the call with
code for the function itself (inline the call).
See the Intel C++ Compiler User's Guide for more complete
information on IPO.
Profile-guided Optimizations (PGO)
Profile-guided optimizations (PGO) tell the compiler which
areas of an application are most frequently executed. By know-
ing these areas, the compiler is able to use feedback from a
previous compilation to be more selective in optimizing the
application. For example, the use of PGO often enables the com-
piler to make better decisions about function inlining, thereby
increasing the effectiveness of interprocedural optimizations.
PGO creates an instrumented program from your source code and
special code from the compiler. Each time this instrumented
code is executed, the instrumented program generates a dynamic
information file. When you compile a second time, the dynamic
information files are merged into a summary file. Using the
profile information in this file, the compiler attempts to
optimize the execution of the most heavily traveled paths in
the program.
The PGO methodology requires three phases:
Phase 1: Instrumentation compilation and linking with
-prof-gen[x]
Phase 2: Instrumented execution by running the executable
Phase 3: Feedback compilation with -prof-use
See the Intel C++ Compiler User's Guide for more complete
information on PGO.
High-level Language Optimizations (HLO)
High-level language optimizations (HLO) exploit the properties
of source code constructs, such as loops and arrays, in appli-
cations developed in high-level programming languages, such as
C++. They include loop interchange, loop fusion, loop
unrolling, loop distribution, unroll-and-jam, blocking, data
prefetch, scalar replacement, data layout optimizations, and
others.
Vectorization Options (i32 only)
The vectorizer is a component of the Intel C++ Compiler that
automatically uses SIMD instructions in the MMX, SSE, and SSE2
instruction sets. The vectorizer detects operations in the pro-
gram that can be executed in parallel, and then converts the
sequential program to process 2, 4, 8, or 16 elements in one
operation, depending on the data type.
The -x{K|W|N|B|P} and -ax{K|W|N|B|P} options enable the vector-
izer. See the Intel C++ Compiler User's Guide for more com-
plete information on the vectorizer.
Auto Parallelization Options
The auto-parallelization feature of the Intel C++ Compiler
automatically translates serial portions of the input program
into equivalent multithreaded code. The auto-parallelizer ana-
lyzes the dataflow of the program's loops and generates multi-
threaded code for those loops which can be safely and effi-
ciently executed in parallel. This enables the potential
exploitation of the parallel architecture found in symmetric
multiprocessor (SMP) systems.
The parallel run-time support provides the same run-time fea-
tures found in OpenMP*, such as handling the details of loop
iteration modification, thread scheduling, and synchronization.
While OpenMP directives enable serial applications to transform
into parallel applications quickly, the programmer must explic-
itly identify specific portions of the application code that
contain parallelism and add the appropriate compiler direc-
tives. Auto-parallelization triggered by the -parallel option
automatically identifies those loop structures that contain
parallelism. During compilation, the compiler automatically
attempts to decompose the code sequences into separate threads
for parallel processing. No other effort by the programmer is
needed.
Parallelization with OpenMP*
The Intel C++ Compiler supports the OpenMP* C++ version 2.0 API
specification. The compiler performs transformations to gener-
ate multithreaded code based on the user's placement of OpenMP
directives in the source program making it easy to add thread-
ing to existing software. The Intel compiler supports all of
the current industry-standard OpenMP directives, except WORK-
SHARE, and compiles parallel programs annotated with OpenMP
directives. In addition, the compiler provides Intel-specific
extensions to the OpenMP C++ version 2.0 specification includ-
ing run-time library routines and environment variables.
Note: As with many advanced features of compilers, you must
properly understand the functionality of the OpenMP directives
in order to use them effectively and avoid unwanted program
behavior.
The Cluster OpenMP* (CLOMP or Cluster OMP) options are avail-
able under a separate license for the Cluster OpenMP product
(i32em, i64 only).
Precompiled Headers
The Intel C++ Compiler supports precompiled header (PCH) files
to significantly reduce compile times using the options
described below. If many of your source files include a common
set of header files, place the common headers first, followed
by the #pragma hdrstop directive. This pragma instructs the
compiler to stop generating PCH files.
For example, if source1.cpp, source2.cpp, and source3.cpp all
include common.h, then place #pragma hdrstop after common.h to
optimize compile times. See the Intel C++ Compiler User's
Guide for more complete information on Precompiled Headers.
Caution: Depending on how you organize the header files listed
in your sources, these options might increase compile time.
PREDEFINED MACROS
The predefined macros available for the Intel C++ Compiler are
described below.
Intel C++ Compiler Predefined Macros
__ARRAY_OPERATORS
Value on IA-32 -- 1
Value on EM64T -- 1
Value on Itanium Architecture -- 1
__BASE_FILE__
Value on IA-32 -- Name of source file
Value on EM64T -- Name of source file
Value on Itanium Architecture -- Name of source file
_BOOL Value on IA-32 -- 1
Value on EM64T -- 1
Value on Itanium Architecture -- 1
__cplusplus
Value on IA-32 -- 1
Value on EM64T -- 1
Value on Itanium Architecture -- 1
__DEPRECATED
Value on IA-32 -- 1
Value on EM64T -- 1
Value on Itanium Architecture -- 1
__EDG__
Value on IA-32 -- 1
Value on EM64T -- 1
Value on Itanium Architecture -- 1
__EDG_VERSION__
Value on IA-32 -- 304
Value on EM64T -- 304
Value on Itanium Architecture -- 304
__ELF__
Value on IA-32 -- 1
Value on EM64T -- 1
Value on Itanium Architecture -- 1
__EXCEPTIONS
Value on IA-32 -- Defined as 1 when -fno-exceptions is
not used.
Value on EM64T -- Defined as 1 when -fno-exceptions is
not used.
Value on Itanium Architecture -- Defined as 1 when
-fno-exceptions is not used.
__extension__
Value on IA-32 -- no value
Value on EM64T -- no value
Value on Itanium Architecture -- no value
__GNUC__
Values on IA-32, EM64T, or Itanium Architecture --
2 -- if gcc version is less than 3.2
3 -- if gcc version is 3.2, 3.3, or 3.4
4 -- if gcc version is 4.x
__GNUC_MINOR__
Values on IA-32, EM64T, or Itanium Architecture --
95 -- if gcc version is less than 3.2
2 -- if gcc version is 3.2
3 -- if gcc version is 3.3
4 -- if gcc version is 3.4
__GNUC_PATCHLEVEL__
Values on IA-32, EM64T, or Itanium Architecture --
3 -- if gcc version is 3.x
__gnu_linux__
Value on IA-32 -- 1
Value on EM64T -- 1
Value on Itanium Architecture -- 1
__GXX_ABI_VERSION
Value on IA-32 -- 102
Value on EM64T -- 102
Value on Itanium Architecture -- 102
__HONOR_STD
Value on IA-32 -- 1
Value on EM64T -- 1
Value on Itanium Architecture -- NA
__i386 Value on IA-32 -- 1
Value on EM64T -- NA
Value on Itanium Architecture -- NA
__i386__
Value on IA-32 or EM64T -- 1
Value on EM64T -- NA
Value on Itanium Architecture -- NA
i386 Value on IA-32 -- 1
Value on EM64T -- NA
Value on Itanium Architecture -- NA
__ia64 Value on IA-32 -- NA
Value on EM64T -- NA
Value on Itanium Architecture -- 1
__ia64__
Value on IA-32 -- NA
Value on EM64T -- NA
Value on Itanium Architecture -- 1
__ICC Value on IA-32 -- 910
Value on EM64T -- 910
Value on Itanium Architecture -- NA
Notes -- Assigned value refers to the compiler (e.g.,
800 is 8.00). Supported for legacy reasons. Use
__INTEL_COMPILER instead.
_INTEGRAL_MAX_BITS
Value on IA-32 -- NA
Value on EM64T -- NA
Value on Itanium Architecture -- 64
__INTEL_COMPILER
Value on IA-32 -- 910
Value on EM64T -- 910
Value on Itanium Architecture -- 910
Notes -- Defines the compiler version. Defined as 910
for the Intel C++ Compiler 9.1.
__INTEL_COMPILER_BUILD_DATE=<YYYYMMDD>
Notes -- Defines the compiler build date. This date
should correspond to the date on the compiler version
banner. Applies to IA-32, EM64T, and Itanium Architec-
ture.
__INTEL_CXXLIB_ICC
Notes -- Is defined (default) as 1 when the -cxxlib-icc
option is specified during compilation. Applies to both
IA-32 and Itanium Architecture, but not to EM64T.
__INTEL_RTTI__
Notes -- Is defined (default) when the -frtti option is
specified for the Intel Linux C++ compiler (i.e., when
RTTI support is enabled). It is disabled when the the
-fno-rtti option is specified for the Intel Linux C++
compiler. Applies to IA-32, EM64T, and Itanium Archi-
tecture.
__INTEL_STRICT_ANSI__
Notes -- Is defined (default) as 1 when the
-strict_ansi option is specified for the Intel Linux C++
compiler (i.e., strict ANSI conformance dialect).
Applies to IA-32, EM64T, and Itanium Architecture.
__itanium__
Value on IA-32 -- NA
Value on EM64T -- NA
Value on Itanium Architecture -- 1
__linux
Value on IA-32 -- 1
Value on EM64T -- 1
Value on Itanium Architecture -- 1
__linux__
Value on IA-32 -- 1
Value on EM64T -- 1
Value on Itanium Architecture -- 1
linux Value on IA-32 -- 1
Value on EM64T -- 1
Value on Itanium Architecture -- 1
__LONG_DOUBLE_SIZE__
Value on IA-32 -- 80
Value on EM64T -- 80
Value on Itanium Architecture -- 80
__LONG_MAX__
Value on IA-32 -- NA
Value on EM64T -- 9223372036854775807L
Value on Itanium Architecture -- 9223372036854775807L
__lp64 Value on IA-32 -- NA
Value on EM64T -- NA
Value on Itanium Architecture -- 1
__LP64__
Value on IA-32 -- NA
Value on EM64T -- 1
Value on Itanium Architecture -- 1
_LP64 Value on IA-32 -- NA
Value on EM64T -- 1
Value on Itanium Architecture -- 1
_MT Value on IA-32 -- NA
Value on EM64T -- 1
Value on Itanium Architecture -- NA
__MMX__
Value on IA-32 -- NA
Value on EM64T -- 1
Value on Itanium Architecture -- NA
__NO_INLINE__
Value on IA-32 -- 1
Value on EM64T -- 1
Value on Itanium Architecture -- 1
__NO_MATH_INLINES
Value on IA-32 -- 1
Value on EM64T -- 1
Value on Itanium Architecture -- 1
__NO_STRING_INLINES
Value on IA-32 -- 1
Value on EM64T -- 1
Value on Itanium Architecture -- 1
_OPENMP
Value on IA-32 -- 200203
Value on EM64T -- 200203
Value on Itanium Architecture -- 200203
Notes -- Defined when -openmp is used.
__OPTIMIZE__
Value on IA-32 -- 1
Value on EM64T -- 1
Value on Itanium Architecture -- 1
Notes -- Not enabled if all optimizations are turned
off.
__pentium4
Value on IA-32 -- NA
Value on EM64T -- 1
Value on Itanium Architecture -- NA
__pentium4__
Value on IA-32 -- NA
Value on EM64T -- 1
Value on Itanium Architecture -- NA
__PIC__
Value on IA-32 -- 1
Value on EM64T -- 1
Value on Itanium Architecture -- 1
Notes -- Defined when -fPIC is used.
__pic__
Value on IA-32 -- 1
Value on EM64T -- 1
Value on Itanium Architecture -- 1
Notes -- Defined when -fPIC is used.
_PGO_INSTRUMENT
Value on IA-32 -- 1
Value on EM64T -- 1
Value on Itanium Architecture -- 1
Notes -- Defined when compiled with either
-prof_gen or -prof_genx.
_PLACEMENT_DELETE
Value on IA-32 -- 1
Value on EM64T -- 1
Value on Itanium Architecture -- 1
__PTRDIFF_TYPE__
Value on IA-32 -- int
Value on EM64T -- long
Value on Itanium Architecture -- long
__REGISTER_PREFIX__
Value on IA-32 -- no value
Value on EM64T -- no value
Value on Itanium Architecture -- no value
__SIGNED_CHARS__
Value on IA-32 -- 1
Value on EM64T -- 1
Value on Itanium Architecture -- 1
__SIZE_TYPE__
Value on IA-32 -- unsigned
Value on EM64T -- unsigned long
Value on Itanium Architecture -- unsigned long
__SSE__
Value on IA-32 -- NA
Value on EM64T -- 1
Value on Itanium Architecture -- NA
__SSE2__
Value on IA-32 -- NA
Value on EM64T -- 1
Value on Itanium Architecture -- NA
__unix Value on IA-32 -- 1
Value on EM64T -- 1
Value on Itanium Architecture -- 1
__unix__
Value on IA-32 -- 1
Value on EM64T -- 1
Value on Itanium Architecture -- 1
unix Value on IA-32 -- 1
Value on EM64T -- 1
Value on Itanium Architecture -- 1
__USER_LABEL_PREFIX__
Value on IA-32 -- (no value)
Value on EM64T -- (no value)
Value on Itanium Architecture -- (no value)
__WCHAR_T
Value on IA-32 -- 1
Value on EM64T -- 1
Value on Itanium Architecture -- 1
__WCHAR_TYPE__
Value on IA-32 -- long int
Value on EM64T -- int
Value on Itanium Architecture -- int
__WINT_TYPE__
Value on IA-32 -- unsigned int
Value on EM64T -- unsigned int
Value on Itanium Architecture -- unsigned int
__x86_64
Value on IA-32 -- NA
Value on EM64T -- 1
Value on Itanium Architecture -- NA
__x86_64__
Value on IA-32 -- NA
Value on EM64T -- 1
Value on Itanium Architecture -- NA
ANSI/ISO Macros Included with the Compiler
The ANSI/ISO standard for C language requires that cer-
tain predefined macros be supplied with conforming com-
pilers. The Intel C++ Compiler supplies the following
macros in accordance with this standard, as well as
additional predefined macros:
__DATE__
The date of compilation as a string literal in
the form Mmm dd yyyy.
__FILE__
A string literal representing the name of the
file being compiled.
__LINE__
The current line number as a decimal constant.
__STDC__
The name __STDC__ is defined when compiling a C
translation unit.
__STDC_HOSTED__
The __STDC_HOSTED__ macro has a value of 1.
__TIME__
The time of compilation. As a string literal in
the form hh:mm:ss.
gcc Predefined Macros
The Intel C++ Compiler includes the following predefined
interoperability macros also supportedby gcc:
__GNUC__
__GNUC_MINOR__
__GNUC_PATCHLEVEL__
You can specify the -no-gcc option if you do not want
these macros defined. If you need gcc interoperability
(-cxxlib-gcc), do not use the -no-gcc compiler option.
Suppress Macro Definition
Use the -Uname option to suppress any macro definition
currently in effect for the specified name. The -U
option performs the same function as an #undef prepro-
cessor directive.
ENVIRONMENT VARIABLES
You can customize your environment by setting the fol-
lowing environment variables. You can specify paths
where the compiler can search for special files such as
libraries and include files.
DYLD_LIBRARY_PATH (M*X32 only)
Specifies the location for all Intel-provided
shared dynamic libraries. At runtime, the linker
will search the colon-separated list of directo-
ries defined by the DYLD_LIBRARY_PATH environment
variable. A DYLD_* set of environment variables
are all used by "dyld", the dynamic link editor.
The full DYLD_* set is documented in "man dyld"
on the MacOS*.
GXX_ROOT
Specifies the location of the gcc binaries. Set
this variable only when the compiler cannot
locate the gcc binaries when using the -gcc-name
option.
GXX_INCLUDE
Specifies the location of the gcc headers. Set
this variable only when the compiler cannot
locate the gcc headers when using the -gcc-name
option.
IA32ROOT (i32, 132em only)
Points to the directory containing the bin, lib,
include and substitute header directories.
IA64ROOT (i64 only)
Points to the directory containing the bin, lib,
include and substitute header directories.
ICCCFG Specifies the configuration file for customizing
compilations with the icc compiler.
ICPCCFG
Specifies the configuration file for customizing
compilations with the icpc compiler.
INTEL_LICENSE_FILE
Specifies the location for the Intel license
file.
LD_LIBRARY_PATH (L*X only)
Specifies the location for all Intel-provided
libraries. The LD_LIBRARY_PATH environment vari-
able contains a colon-separated list of directo-
ries in which the linker will search for library
(.a) files. If you want the linker to search
additional libraries, you can add their names to
LD_LIBRARY_PATH, to the command line, to a
response file, or to the configuration file. In
each case, the names of these libraries are
passed to the linker before the names of the
Intel libraries that the driver always specifies.
PATH Specifies the directories the system searches for
binary executable files.
TMP Specifies the directory in which to store tempo-
rary files. If the directory specified by TMP
does not exist, the compiler places the temporary
files in the current directory. If a directory
is not specified, the compiler stores temporary
files in /tmp.
TMPDIR Same as TMP.
TEMP Same as TMP.
GNU* Environment Variables
The Intel C++ Compiler supports the following GNU envi-
ronment variables:
C_INCLUDE_PATH
Specifies a list of directories to include for C
compilations.
CPATH Specifies a list of directories to include for C
or C++ compilations.
CPLUS_INCLUDE_PATH
Specifies a list of directories to include for
C++ compilations.
DEPENDENCIES_OUTPUT
If this variable is set, its value specifies how
to output dependencies for Make based on the non-
system header files processed by the compiler.
System header files are ignored in the dependency
output.
LIBRARY_PATH
The value of LIBRARY_PATH is a colon-separated
list of directories, much like PATH.
SUNPRO_DEPENDENCIES
This variable is the same as DEPENDENCIES_OUTPUT,
except that system header files are not ignored.
Compilation Environment Options
The Intel C++ Compiler installation includes shell
scripts that you can use to set environment variables.
See the Intel C++ User's Guide for more information.
Standard OpenMP Environment Variables
OMP_DYNAMIC
Enables (.TRUE.) or disables (.FALSE.) the
dynamic adjustment of the number of threads.
DEFAULT: .FALSE.
OMP_NESTED
Enables (.TRUE.) or disables (.FALSE.) nested
parallelism.
DEFAULT: .FALSE.
OMP_NUM_THREADS
Sets the number of threads to use during execu-
tion.
DEFAULT: Number of processors currently installed
in the system while generating the executable
OMP_SCHEDULE
Specifies the run-time schedule type and chunk
size.
DEFAULT: STATIC, no chunk size specified
Intel Extensions to OpenMP Environment Variables
KMP_ALL_THREADS
Sets the maximum number of threads that can be
used by any parallel region.
DEFAULT: max(32, 4 * OMP_NUM_THREADS, 4 * number
of processors)
KMP_BLOCKTIME
Sets the time (in milliseconds) that a thread
should wait after completing the execution of a
parallel region, before sleeping. See also the
throughput execution mode section of the User
documentation, and the KMP_LIBRARY environment
variable. Use the optional character suffix s, m,
h, or d, to specify seconds, minutes, hours, or
days
DEFAULT: 200 milliseconds
KMP_LIBRARY
Selects the OpenMP run-time library throughput.
The options for the variable value are: serial,
turnaround, or throughput indicating the execu-
tion mode. The default value of throughput is
used if this variable is not specified.
DEFAULT: throughput (execution mode)
KMP_MONITOR_STACKSIZE
Sets the number of bytes to allocate for the mon-
itor thread (used for book-keeping during program
execution). U se the optional suffix b, k, m, g,
or t, to specify bytes, kilobytes, megabytes,
gigabytes, or terabytes.
DEFAULT: max(32k, system minimum thread stack
size)
KMP_STACKSIZE
Sets the number of bytes to allocate for each
parallel thread to use as its private stack. Use
the optional suffix b, k, m, g, or t, to specify
bytes, kilobytes, megabytes, gigabytes, or ter-
abytes.
DEFAULT:
i32: 2m
i64: 4m
KMP_VERSION
Enables (set) or disables (unset) the printing of
OpenMP run-time library version information dur-
ing program execution.
DEFAULT: Disabled
PGO Environment Variables
The following environment values determine the directory
in which to store dynamic information files or whether
to overwrite pgopti.dpi.
PROF_DIR
Specifies the directory in which dynamic informa-
tion files are created. This variable applies to
all three phases of the profiling process.
PROF_DUMP_INTERVAL
Initiate Interval Profile Dumping in an instru-
mented application. The _PGOPTI_Set_Inter-
val_Prof_Dump(int interval) function activates
Interval Profile Dumping and sets the approximate
frequency at which dumps will occur. The inter-
val parameter is measured in milliseconds and
specifies the time interval at which profile
dumping will occur. An alternative method of ini-
tiating Interval Profile Dumping is by setting
this environment variable. Set this environment
variable to the desired interval value prior to
starting the application.
PROF_NO_CLOBBER
Alters the feedback compilation phase slightly.
By default, during the feedback compilation
phase, the compiler merges the data from all
dynamic information files and creates a new
pgopti.dpi file, if the .dyn files are newer than
an existing pgopti.dpi file.
When this variable is set, the compiler does not
overwrite the existing pgopti.dpi file. Instead,
the compiler issues a warning and you must remove
the pgopti.dpi file if you want to use additional
dynamic information files.
EXAMPLES
The following examples demonstrate optimizing across
multiple input files:
1. icc ax.cpp
This command compiles the C++ file 'ax.cpp'
producing executable file 'a.out'. Optimizations
occur by default.
2. icc -o abc ax.cpp bx.cpp cx.cpp
This command uses option -o to name the
executable file 'abc' and compiles 'ax.cpp',
'bx.cpp', and 'cx.cpp' as one program.
3. icc -c ax.cpp bx.cpp cx.cpp
This command uses option -c to suppress
linking and produce individual object
files 'ax.o', 'bx.o', and 'cx.o'. Interprocedural
optimizations are prevented.
4. icc -c ay.c
This command compiles the C file 'ay.c' and the
-c option suppresses linking to produce of an
object file 'ay.o'.
5. icpc -c by.cpp
This command compiles the C++ file 'by.cpp' and
the -c option suppresses linking to produce an
object file 'by.o'.
6. icpc ay.o by.o
This command links the two object files 'ay.o'
and 'by.o' and produces an executable
file 'a.out'.
7. icc -c -O1 sub2.cpp
icc -c -O1 sub3.cpp
icc -o main.exe -g -O0 main.cpp sub2.o sub3.o
The first two commands show incremental
compilation with minimal optimization.
The first command generates an object
file of 'sub2'; the second generates
an object file of 'sub3'.
The last command uses option -O0 to
disable all compiler default optimizations.
It uses option -g to generate symbolic
debugging information and line numbers in
the object code, which can be used by a
source-level debugger.
TECHNICAL SUPPORT
The Intel C++ Compiler product web site offers timely
and comprehensive product information, including product
features, white papers, and technical articles. For the
latest information, visit http://devel-
oper.intel.com/software/products/.
Intel also provides a support web site that contains a
rich repository of self help information, including get-
ting started tips, known product issues, product errata,
license information, user forums, and more.
Registering your product entitles you to one year of
technical support and product updates through Intel Pre-
mier Support. Intel Premier Support is an interactive
issue management and communication web site that enables
you to submit issues and review their status, and to
download product updates anytime of the day.
To register your product, contact Intel, or seek product
support, please visit: http://www.intel.com/soft-
ware/products/support.
SEE ALSO
The Intel C++ Compiler User's Guide is the definitive
source for detailed information on using the Intel C++
Compiler, including a complete listing of all compiler
options, and much more.
In addition, see these other documents:
· Product Release Notes
· Intel Itanium Assembler User's Guide
· Intel Itanium Architecture Assembly Language Refer-
ence Guide
You can access these documents from
<install-dir>/doc/Doc_Index.htm or from http://devel-
oper.intel.com/software/products/compilers/ .
COPYRIGHT INFORMATION
Copyright (C) 2002 - 2006, Intel Corporation. All rights
reserved.
* Other brands and names are the property of their
respective owners.
SYNOPSIS
ifort [ options ] file1 [ file2 ]...
options
Are zero or more compiler options.
fileN Is a Fortran source file, assembly file, object file, object
library, or other linkable file.
DESCRIPTION
The ifort command invokes the Intel(R) Fortran Compiler that is
designed to preprocess, compile, assemble, and link Fortran programs
on Intel(R) IA-32-based systems, Intel IA-32-based systems with
Intel(R) Extended Memory 64 Technology (Intel(R) EM64T), or Intel(R)
Itanium(R)-based systems. For more information on this compiler, see
the Intel(R) Fortran Building Applications guide.
The ifort command interprets input files by their filename suffix as
follows:
· Filenames with the suffix .f90 are interpreted as free-form
Fortran 95/90 source files.
· Filenames with the suffix .f, .for, or .ftn are interpreted as
fixed-form Fortran source files.
· Filenames with the suffix .fpp, .F, .FOR, .FTN, or .FPP are
interpreted as fixed-form Fortran source files, which must be
preprocessed by the fpp preprocessor before being compiled.
· Filenames with the suffix .F90 are interpreted as free-form
Fortran source files, which must be preprocessed by the fpp
preprocessor before being compiled.
· Filenames with the suffix .s are interpreted as assembler files
and are passed to the assembler.
· Filenames with the suffix .S are interpreted as assembler files
and are preprocessed by the fpp preprocessor before being
passed to the assembler.
· Filenames with the suffix .a are interpreted as object
libraries and are passed to ld(1).
· Filenames with the suffix .o are interpreted as compiled object
files and are passed to ld(1).
You can override some options specified on the command line by using
the OPTIONS statement in your Fortran source program. An OPTIONS
statement affects only the program unit in which the statement occurs.
For more information, see the Intel(R) Fortran Language Reference.
Most language features are available on all supported systems. How-
ever, some language features are only available on certain processors
or a certain operating system. Such language features are labeled
within parentheses as follows:
i32 Means the feature is available on IA-32-based systems.
i32em Means the feature is available on IA-32-based systems with
Intel(R) Extended Memory 64 Technology (Intel(R) EM64T).
i64 Means the feature is available on Itanium(R)-based systems.
L*X Means the feature is available on Linux* systems.
M*X32 Means the feature is available on Intel(R)-based systems run-
ning Mac OS*.
If a labeled feature is only available on one processor or one operat-
ing system, you will see the word "only" within the label. If no
label appears, the language feature is available on all supported sys-
tems.
Performance Enhancing Options
The following command line options can be used to increase the run-
time performance of code generated by the Intel Fortran compiler:
· On IA-32-based systems (including those with Intel(R) EM64T):
-ax<p>, -ftz, -ip, -ipo, -O[n], -openmp, -parallel, -prof-use,
-tpp<n>, -x<p>.
· On Itanium(R)-based systems: -fnsplit, -ftz, -ip, -ipo, -O[n],
-openmp, -parallel, -prof-use, -tpp<n>.
Configuration and Indirect Files
Command options to be used whenever the compiler is invoked can be put
into a system configuration file named ifort.cfg, which resides in the
same area as the compiler. The text in this file is processed by
ifort before the text on the command line. To use a personal configu-
ration file, set the environment variable IFORTCFG to point to the
path and filename to be used.
An indirect file contains text that can be included on the ifort com-
mand line. Precede the filename with an at symbol (@) on the command
line at the point where the options are to be inserted. For example,
assume file double_size contains options "-i8 -r8" and file
my_includes contains options "-I/bld/inc -I/bld/headers". In this
case, the following command line:
ifort -O3 @double_size myprog.f90 @my_includes
passes "-O3 -i8 -r8 myprog.f90 -I/bld/inc -I/bld/headers" to the com-
piler.
OPTIONS
Some compiler options have the form -name keyword. -name must be
spelled out completely, but keyword can be abbreviated to its shortest
unique prefix (4 characters are recommended). For example, -assume
buffered_io can be specified as -assume buff.
For information on linker and load-time options, see ld(1).
For some options, you can (or must) specify additional information,
such as a keyword, a directory, a file name, a number, and so forth.
When this information is required, it is shown in angle brackets (<>);
when it is optional, it is shown in square brackets ([]). For exam-
ple, in option -align <keyword>, keyword is required; in option
-unroll[n], n (a number) is optional.
The ifort command takes the following options:
-1 Tells the compiler to execute at least one iteration of DO
loops (same as the -onetrip option). This option has the same
effect as -f66.
-66 Enforces FORTRAN 66 semantics (same as the -f66 option).
-72 Specifies that the statement field of each fixed-form source
line ends at column 72. This is the default.
-80 Specifies that the statement field of each fixed-form source
line ends at column 80.
-132 Specifies that the statement field of each fixed-form source
line ends at column 132 (same as the -extend_source option).
-align [keyword]
Tells the compiler how to align certain data items. The follow-
ing are -align options:
· -align all
Tells the compiler to add padding bytes whenever possible to
obtain the natural alignment of data items in common blocks,
derived types, and record structures. Specifies -align
nocommons, -align dcommons, -align records, -align nose-
quence. This is the same as specifying -align with no key-
word.
· -align commons
Aligns all common block entities on natural boundaries up to
4 bytes, by adding padding bytes as needed. The default is
-align nocommons, which adds no padding to common blocks.
· -align dcommons
Aligns all common block entities on natural boundaries up to
8 bytes, by adding padding bytes as needed. If you specify
any -std option or the -stand f90 or -stand f95 option, this
option is ignored. The default is -align nodcommons, which
adds no padding to common blocks.
· -align none
Tells the compiler not to add padding bytes anywhere in com-
mon blocks or structures. This is the same as specifying
-noalign. The default is to add no padding to common blocks
but to add padding to structures.
· -align norecords
Aligns components of derived types and fields within record
structures on arbitrary byte boundaries with no padding. The
default is -align records.
· -align rec<n>byte
Aligns fields of records and components of derived types on
the smaller of the size boundary specified or the boundary
that will naturally align them. <n> can be 1, 2, 4, 8, or
16.
· -align sequence
Aligns components of a derived type declared with the
SEQUENCE statement (sequenced components) according to the
alignment rules that are currently in use. The default
alignment rules are to align unsequenced components on natu-
ral boundaries. The default is -align nosequence, which
requests that sequenced components be packed regardless of
any other alignment rules. If you specify any -std option or
the -stand f90 or -stand f95 option, this option is ignored.
The defaults for -align are nocommons, nodcommons, records, and
nosequence.
-allow nofpp_comments
Tells the compiler to disallow Fortran-style end-of-line com-
ments on preprocessor lines. This means comment indicators have
no special meaning.
This option can be useful when you want to have a Fortran
directive as a define value. The default is -allow fpp_com-
ments, which tells the compiler to recognize Fortran-style end-
of-line comments on preprocessor lines.
-arch <keyword> (i32 and i32em)
Determines the version of the architecture for which the com-
piler generates instructions. The following are -arch options:
· -arch pn1
Optimizes for the Intel(R) Pentium(R) processor.
· -arch pn2
Optimizes for the Intel(R) Pentium(R) Pro, Intel(R) Pen-
tium(R) II, and Intel(R) Pentium(R) III processors.
· -arch pn3
Optimizes for the Intel(R) Pentium(R) Pro, Intel(R) Pen-
tium(R) II, and Intel(R) Pentium(R) III processors. This is
the same as specifying the -arch pn2 option.
· -arch pn4
Optimizes for the Intel(R) Pentium(R) 4 processor. This is
the default.
· -arch SSE
Optimizes for Intel Pentium 4 processors with Streaming SIMD
Extensions (SSE).
· -arch SSE2
Optimizes for Intel Pentium 4 processors with Streaming SIMD
Extensions 2 (SSE2).
The only options available on Intel(R) EM64T systems are -arch
pn1, -arch pn2, -arch pn3, and -arch pn4.
-assume <keyword>
Tells the compiler to make certain assumptions. The following
are -assume options:
· -assume bscc
Tells the compiler to treat the backslash character (\) as a
C-style control (escape) character syntax in character liter-
als. The default is -assume nobscc, which tells the compiler
to treat the backslash character as a normal character
instead of a control character in character literals.
· -assume buffered_io
Tells the compiler to accumulate records in a buffer. This
sets the default for opening sequential output files to
BUFFERED='YES', which also occurs if the FORT_BUFFERED run-
time environment variable is specified. The default is
-assume nobuffered_io, which means that data will be immedi-
ately written to disk.
· -assume byterecl
Specifies that the units for the OPEN statement RECL speci-
fier (record length) value are in bytes for unformatted data
files, not longwords (four-byte units). For formatted files,
the RECL unit is always in bytes. The default is -assume
nobyterecl.
INQUIRE returns RECL in bytes if the unit is not open.
INQUIRE returns RECL in longwords if the file is open for
unformatted data (and -assume byterecl is not specified);
otherwise, it returns RECL in bytes.
· -assume cc_omp
Enables conditional compilation as defined by the OpenMP For-
tran API. That is, when !$space appears in free-form source
or c$spaces appears in column 1 of fixed-form source, the
rest of the line is accepted as a Fortran line. If -openmp
is specified, the default is -assume cc_omp; otherwise, the
default is -assume nocc_omp.
· -assume dummy_aliases
Tells the compiler that dummy (formal) arguments to proce-
dures share memory locations with other dummy arguments
(aliases) or with variables shared through use association,
host association, or common block use. These program seman-
tics slow performance and do not strictly obey the Fortran
95/90 Standards. The default is -assume nodummy_aliases.
· -assume minus0
Tells the compiler to use Fortran 95 standard semantics for
the treatment of the IEEE* floating value -0.0 in the SIGN
intrinsic, which distinguishes the difference between -0.0
and +0.0, and to write a value of -0.0 with a negative sign
on formatted output.
The default is -assume nominus0, which tells the compiler to
use Fortran 90/77 standard semantics in the SIGN intrinsic to
treat -0.0 and +0.0 as 0.0, and to write a value of 0.0 with
no sign on formatted output.
· -assume none
Disables all the -assume options.
· -assume noprotect_constants
Tells the compiler to pass a copy of a constant actual argu-
ment. This copy can be modified by the called routine, even
though the Fortran standard prohibits such modification. The
calling routine does not see any modification to the con-
stant. The default is -assume protect_constants, which passes
the constant actual argument. Any attempt to modify it
results in an error.
· -assume nosource_include
Tells the compiler to search the default directory for module
files specified by a USE statement or source files specified
by an INCLUDE statement. The default is -assume
source_include, which tells the compiler to search the direc-
tory the source file is in for any INCLUDE files or modules.
· -assume nounderscore
Tells the compiler not to append an underscore character to
external user-defined names: the main program name, named
common blocks, BLOCK DATA blocks, global data names in MOD-
ULEs, and names implicitly or explicitly declared EXTERNAL.
The name of a blank (unnamed) common block remains _BLNK__,
and Fortran intrinsic names are not affected. The default is
-assume underscore.
· -assume 2underscores
Tells the compiler to append two underscore characters to
external user-defined names that contain an embedded under-
score: the main program name, named common blocks, BLOCK DATA
blocks, global data names in MODULEs, and names implicitly or
explicitly declared EXTERNAL. The name of a blank (unnamed)
common block remains _BLNK__, and Fortran intrinsic names are
not affected. The default is -assume no2underscores.
This option does not affect external names that do not con-
tain an embedded underscore. By default, the compiler only
appends one underscore to those names.
· -assume writeable-strings
Tells the compiler to put character constants into non-read-
only memory. The default is -assume nowriteable-strings.
-auto Causes all local, non-SAVEd variables to be allocated on the
run-time stack (same as -automatic or -nosave). The default is
-auto-scalar. However, if you specify -recursive or -openmp,
the default is -automatic.
-auto-scalar
Causes allocation of scalar variables of intrinsic types INTE-
GER, REAL, COMPLEX, and LOGICAL to the run-time stack. This is
the default. However, if you specify -recursive or -openmp, the
default is -automatic.
You cannot specify -save, -auto, or -automatic with this
option.
-autodouble
Makes default real and complex variables 8 bytes long. REAL
declarations are treated as DOUBLE PRECISION (REAL(KIND=8)) and
COMPLEX declarations are treated as DOUBLE COMPLEX (COM-
PLEX(KIND=8)). This option is the same as specifying -real_size
64 or -r8.
-automatic
Causes all local, non-SAVEd variables to be allocated on the
run-time stack (same as -auto or -nosave). The default is
-auto-scalar. However, if you specify -recursive or -openmp,
the default is -automatic.
-ax<p> (i32 and i32em)
Generates processor-specific code if there is a performance
benefit, while also generating generic IA-32 code. The
characters K, W, N, B, and P denote the processor types (<p>).
The following are -ax options:
· -axK
Generates code for Intel Pentium III processors and compati-
ble Intel processors.
· -axW
Generates code for Intel Pentium 4 processors and compatible
Intel processors.
· -axN
Generates code for Intel Pentium 4 processors and compatible
Intel processors. Also enables new optimizations in addition
to Intel processor-specific optimizations.
· -axB
Generates code for Intel Pentium M processors and compatible
Intel processors. Also enables new optimizations in addition
to Intel processor-specific optimizations.
· -axP
Generates code for Intel(R) Core(TM) Duo processors, Intel(R)
Core(TM) Solo processors, Intel(R) Pentium(R) 4 processors
with Streaming SIMD Extensions 3, and compatible Intel pro-
cessors with Streaming SIMD Extensions 3. This option also
enables new optimizations in addition to Intel processor-spe-
cific optimizations.
The only options available on Intel(R) EM64T systems are -axW
and -axP. On Mac OS systems, the only valid option is -axP.
On these systems, it is equivalent to -xP, which is the default
and is always set.
You can use more than one of the -ax options by combining the
characters that denote the processor type. For example, you
can specify -axNB to generate code for Intel(R) Pentium(R) 4
processors and Intel Pentium M processors.
If you specify both the -ax and -x options, the generic code
will only execute on processors compatible with the processor
type specified by the -x option.
-B<dir>
Specifies a directory that can be used to find include files,
libraries, and executables. The compiler uses <dir> as a pre-
fix.
For include files, the <dir> is converted to -I/<dir>/include.
This command is added to the front of the includes passed to
the preprocessor.
For libraries, the <dir> is converted to -L/<dir>. This com-
mand is added to the front of the standard -L inclusions before
system libraries are added.
For executables, if <dir> contains the name of a tool, such as
ld or as, the compiler will use it instead of those found in
the default directories.
The compiler looks for include files in <dir>/include while
library files are looked for in <dir>.
-Bdynamic (L*X only)
Enables dynamic linking of libraries at run time. Smaller exe-
cutables are created than with static linking.
-Bstatic (L*X only)
Enables static linking of a user-created library.
-c Prevents linking. It causes the compiler to compile to an
object (.o) file only.
-C Enables all checks on run-time conditions (same as the -check
all option).
-CB Performs run-time checks on whether array subscript and sub-
string references are within declared bounds (same as the
-check bounds option).
-ccdefault <keyword>
Specifies the type of carriage control used when a file is dis-
played at a terminal screen (units 6 and *). The following are
-ccdefault options:
· -ccdefault default
Specifies that the compiler is to use the default carriage-
control setting. This is the default.
The default setting can be affected by the -vms option: if
"-vms -ccdefault default" is specified, carriage control
defaults to FORTRAN if the file is formatted, and the unit is
connected to a terminal; if "-novms -ccdefault default" is
specified, carriage control defaults to LIST.
· -ccdefault fortran
Specifies normal Fortran interpretation of the first charac-
ter.
· -ccdefault list
Specifies one line feed between records.
· -ccdefault none
Specifies no carriage control processing.
-check [keyword]
Checks for certain conditions at run time. The following are
-check options:
· -check all
Enables all -check options. This is the same as specifying
-check with no keyword.
· -check arg_temp_created
Generates code to check if actual arguments are copied into
temporary storage before routine calls. If a copy is made at
run time, an informative message is displayed. The default
is -check noarg_temp_created.
· -check bounds
Performs run-time checks on whether array subscript and sub-
string references are within declared bounds. The default is
-check nobounds.
· -check format
Issues the run-time FORVARMIS fatal error when the data type
of an item being formatted for output does not match the for-
mat descriptor being used (for example, a REAL*4 item format-
ted with an I edit descriptor). If -vms is specified, the
default is -check format; otherwise, the default is -check
noformat.
With -check noformat, the data item is formatted using the
specified descriptor unless the length of the item cannot
accommodate the descriptor (for example, it is still an error
to pass an INTEGER*2 item to an E edit descriptor).
· -check none
Disables all -check options. This is the default. This is
the same as specifying -nocheck.
· -check output_conversion
Issues the run-time OUTCONERR continuable error message when
a data item is too large to fit in a designated format
descriptor field. The field is filled with asterisks (*) and
execution continues. If -vms is specified, the default is
-check output_conversion; otherwise, the default is -check
nooutput_conversion.
· -check uninit
Generates code to check for uninitialized variables. If a
variable is read before written, a run-time error routine
will be called. The default is -check nounit.
To get more detailed location information about where the error
occurred, use -traceback.
-cm Suppresses all messages about questionable programming prac-
tices (same as the -warn nousage option).
-common-args
Tells the compiler that dummy (formal) arguments to procedures
share memory locations with other dummy arguments or with vari-
ables shared through use association, host association, or com-
mon block use. This is the same as specifying -assume
dummy_aliases.
-complex-limited-range
Enables the use of basic algebraic expansions of some arith-
metic operations involving data of type COMPLEX. This can cause
some performance improvements in programs that use a lot of
COMPLEX arithmetic, but values at the extremes of the exponent
range may not compute correctly. The default is -no-complex-
limited-range, which disables this option.
-convert <keyword>
Specifies the format for unformatted files containing numeric
data. The following are -convert options:
· -convert big_endian
Specifies that the format will be big endian for INTEGER*1,
INTEGER*2, INTEGER*4, or INTEGER*8, and big endian IEEE
floating-point for REAL*4, REAL*8, REAL*16, COMPLEX*8, COM-
PLEX*16, or COMPLEX*32.
· -convert cray
Specifies that the format will be big endian for INTEGER*1,
INTEGER*2, INTEGER*4, or INTEGER*8, and CRAY* floating-point
for REAL*8 or COMPLEX*16.
· -convert fdx
Specifies that the format will be little endian for INTE-
GER*1, INTEGER*2, INTEGER*4, or INTEGER*8, and VAX processor
floating-point format F_floating for REAL*4 or COMPLEX*8,
D_floating for REAL*8 or COMPLEX*16, and X_floating for
REAL*16 or COMPLEX*32.
· -convert fgx
Specifies that the format will be little endian for INTE-
GER*1, INTEGER*2, INTEGER*4, or INTEGER*8, and VAX processor
floating-point format F_floating for REAL*4 or COMPLEX*8,
G_floating for REAL*8 or COMPLEX*16, and X_floating for
REAL*16 or COMPLEX*32.
· -convert ibm
Specifies that the format will be big endian for INTEGER*1,
INTEGER*2, or INTEGER*4, and IBM* System\370 floating-point
format for REAL*4 or COMPLEX*8 (IBM short 4) and REAL*8 or
COMPLEX*16 (IBM long 8).
· -convert little_endian
Specifies that the format will be little endian for INTE-
GER*1, INTEGER*2, INTEGER*4, or INTEGER*8, and little endian
IEEE floating-point for REAL*4, REAL*8, REAL*16, COMPLEX*8,
COMPLEX*16, or COMPLEX*32.
· -convert native
Specifies that unformatted data should not be converted. This
is the default.
· -convert vaxd
Specifies that the format will be little endian for INTE-
GER*1, INTEGER*2, INTEGER*4, or INTEGER*8, and VAX processor
floating-point format F_floating for REAL*4 or COMPLEX*8,
D_floating for REAL*8 or COMPLEX*16, and H_floating for
REAL*16 or COMPLEX*32.
· -convert vaxg
Specifies that the format will be little endian for INTE-
GER*1, INTEGER*2, INTEGER*4, or INTEGER*8, and VAX processor
floating-point format F_floating for REAL*4 or COMPLEX*8,
G_floating for REAL*8 or COMPLEX*16, and H_floating for
REAL*16 or COMPLEX*32.
-cpp Runs the Fortran preprocessor on source files prior to compila-
tion (same as the -fpp option).
-cxxlib[-<mode>]
Tells the compiler to link using certain C++ run-time
libraries. The following are -cxxlib <mode>s:
· gcc[=<dir>]
Tells the compiler to link using the C++ run-time libraries
provided with the gcc compiler. <dir> is an optional top-
level location for the gcc binaries and libraries.
· icc
Tells the compiler to link using the C++ run-time libraries
provided by Intel. -cxxlib-icc is only available on IA-32
and Itanium(R)-based Linux systems.
If you specify the option with no <mode>, the compiler uses the
default C++ libraries.
The default on Mac OS systems is -cxxlib-gcc. The default on
Linux systems is -no-cxxlib, which tells the compiler to use
the default run-time libraries and not link to any additional
C++ run-time libraries. This is the same as specifying -no-
cpprt.
-D<name>[=<value>]
Specifies <name> as a definition (symbol) to use with condi-
tional compilation directives or the Fortran preprocessor
(-fpp). <value> can be an integer or it can be a character
string delimited by double quotes; for example,
-Dname="string". If <value> is not specified, <name> is
defined as "1".
-DD Compiles debug statements (indicated by D in column 1); this is
the same as specifying -d_lines.
-d_lines
Compiles debug statements (indicated by D in column 1); this is
the same as specifying -DD. The default is -nod_lines.
-debug [keyword] (L*X only)
Specifies settings that enhance debugging. The following are
-debug options:
· -debug inline_debug_info
Produces enhanced debug information for inlined code. It
provides more information to debuggers for function call
traceback. The default is -debug noinline_debug_info.
· -debug semantic_stepping
Produces enhanced debug information useful for breakpoints
and stepping. It tells the debugger to stop only at machine
instructions that achieve the final effect of a source state-
ment. For example, in the case of an assignment statement,
this might be a store instruction that assigns a value to a
program variable; for a function call, it might be the
machine instruction that executes the call. Other instruc-
tions generated for those source statements are not displayed
during stepping. The default is -debug nosemantic_stepping.
· -debug variable_locations
Produces enhanced debug information useful in finding scalar
local variables. It uses a feature of the Dwarf object mod-
ule known as "location lists". This feature allows the run-
time locations of local scalar variables to be specified more
accurately; that is, whether, at a given position in the
code, a variable value is found in memory or a machine regis-
ter. The default is -debug novariable_locations.
· -debug extended
Sets the debug options semantic_stepping and variable_loca-
tions.
-debug-parameters [keyword]
Tells the compiler to generate debug information for PARAMETERs
used in a program. The following are -debug-parameters
options:
· -debug-parameters none
Generates no debug information for any PARAMETERs used in the
program. This is the default; it is the same as specifying
-nodebug-parameters.
· -debug-parameters used
Generates debug information for only PARAMETERs that have
actually been referenced in the program. This is the same as
specifying -debug-parameters with no keyword.
· -debug-parameters all
Generates debug information for all PARAMETERs defined in the
program.
Note that if a .mod file contains PARAMETERs, debug information
is only generated for the PARAMETERs that have actually been
referenced in the program, even if you specify -debug-parame-
ters all.
-double_size <size>
Defines the default KIND for DOUBLE PRECISION and DOUBLE COM-
PLEX declarations, constants, functions, and intrinsics. <size>
can be 64 (KIND=8) or 128 (KIND=16). The default is -dou-
ble_size 64.
-dryrun
Tells the driver that tool commands should be shown but not
executed. See also -v.
-dynamic-linker<file> (L*X only)
Specifies a dynamic linker (<file>) other than the default.
-dynamiclib (M*X32 only)
Invokes the libtool command to generate dynamic libraries.
When passed this option, GCC on Mac OS uses the libtool command
to produce a dynamic library instead of an executable when
linking.
To build static libraries, you should use "libtool -static
<objects>".
-dyncom "common1,common2,common3"
Enables dynamic allocation of the specified COMMON blocks at
run time. The quotes must be present.
-E Causes the Fortran preprocessor to send output to stdout.
-e90 Causes the compiler to issue errors instead of warnings for
nonstandard Fortran 90 (same as the -warn stderrors option).
No such errors or warnings are issued by default.
-e95 Causes the compiler to issue errors instead of warnings for
nonstandard Fortran (same as the -warn stderrors option). No
such errors or warnings are issued by default.
-EP Causes the Fortran preprocessor to send output to stdout, omit-
ting #line directives.
-error_limit <n>
Specifies the maximum number of error-level or fatal-level com-
piler errors allowed for a file specified on the command line.
If you specify -noerror_limit, there is no limit to the number
of errors that are allowed. The default is -error_limit 30 (a
maximum of 30 error-level and fatal-level messages before the
compiler stops the compilation).
-extend_source [size]
Specifies the column number to use to end the statement field
in fixed-form source files. [size] can be 72, 80, or 132. The
default behavior is -noextend_source, which implies column 72.
If you do not specify size, it is the same as specifying
-extend_source 132.
-F Causes the Fortran preprocessor to send output to a file (same
as the -preprocess_only and -P options). Note that the source
file is not compiled.
-f66 Tells the compiler to apply FORTRAN 66 semantics: the execution
of at least one iteration of DO loops, different EXTERNAL
statement syntax and semantics, and different behavior of the
BLANK= and STATUS= specifiers on the OPEN statement. This is
the same as specifying the -66 option. By default, the com-
piler applies Fortran 95 semantics.
-f77rtl
Tells the compiler to use the run-time behavior of Fortran 77
instead of Intel(R) Fortran. This affects some INQUIRE speci-
fiers when the unit is not connected to a file, PAD= defaults
to 'NO' for formatted input, NAMELIST input format is differ-
ent, and NAMELIST and list-directed input of character strings
must be delimited by apostrophes or quotes. The default is
-nof77rtl.
-fast Maximizes speed across the entire program. On Itanium(R)-based
systems, this option sets options -ipo, -O3, and -static. On
IA-32 and Intel(R) EM64T systems, this option sets options
-ipo, -O3, -no-prec-div, -static, and -xP.
Note that programs compiled with the -xP option will detect
non-compatible processors and generate an error message during
execution.
-fcode-asm
Produces an assembly file with optional machine code annota-
tions. To use this option, you must also specify -S.
-fexceptions
Enables C++ exception handling table generation, preventing
Fortran routines in mixed-language applications from interfer-
ing with exception handling between C++ routines. The default
is -fno-exceptions, which disables C++ exception handling table
generation, resulting in smaller code. When this option is
used, any use of C++ exception handling constructs (such as try
blocks and throw statements) when a Fortran routine is in the
call chain will produce an error.
-FI Specifies source files are in fixed format (same as the -fixed
option).
-finline-limit=<n>
Lets you specify the maximum size of a function to be inlined.
n must be an integer greater than or equal to zero. It is the
maximum number of lines the function can have to be considered
for inlining.
The compiler inlines smaller functions, but this option lets
you inline large functions. For example, to indicate a large
function, you could specify 100 or 1000 for n.
-fixed Specifies source files are in fixed format. By default, source
file format is determined by the file suffix.
-fltconsistency
Enables improved floating-point consistency. Floating-point
operations are not reordered and the result of each floating-
point operation is stored in the target variable rather than
being kept in the floating-point processor for use in a subse-
quent calculation. This is the same as specifying -mp or
-mieee-fp.
The default, -nofltconsistency, provides better accuracy and
run-time performance at the expense of less consistent float-
ing-point results.
-fmath-errno
Tells the compiler to assume that the program tests errno after
calls to math library functions. This restricts optimization
because it causes the compiler to treat most math functions as
having side effects.
The default, -fno-math-errno, tells the compiler to assume that
the program does not test errno after calls to math library
functions. This frequently allows the compiler to generate
faster code. Floating-point code that relies on IEEE excep-
tions instead of errno to detect errors can safely use this
option to improve performance.
-fminshared
Specifies that a compilation unit is a component of a main pro-
gram and will not be linked as part of a shareable object.
-fno-alias
Specifies that aliasing should not be assumed in the program.
The default is -falias.
-fno-fnalias
Specifies that aliasing should not be assumed within functions,
but should be assumed across calls. The default is -ffnalias.
-fno-inline-functions
Disables certain interprocedural optimizations for single file
compilation. The default is -finline-functions, which tells
the compiler to perform inline function expansion for calls to
functions defined within the current source file.
-fno-omit-frame-pointer (i32 and i32em)
Disables use of EBP as a general purpose register so it can be
used as a stack frame pointer. This is the same as specifying
-fp. The default, -fomit-frame-pointer, enables EBP to be used
as a general purpose register.
-fnsplit (i64 only; L*X only)
Enables function splitting if -prof-use is also specified. Oth-
erwise, the default is -no-fnsplit, which disables the split-
ting within a routine but leaves function grouping enabled.
-fp (i32 and i32em)
Disables use of EBP as a general purpose register so it can be
used as a stack frame pointer. By default, EBP is used as a
general purpose register. This is the same as specifying
-fno-omit-frame-pointer.
-fpconstant
Tells the compiler to extend the precision to double precision
for single-precision constants assigned to double-precision
variables. The default is -nofpconstant.
-fpe<n>
Specifies floating-point exception handling for the main pro-
gram at run-time. You can specify one of the following values
for <n>:
0 - Floating-point invalid, divide-by-zero, and overflow excep-
tions are enabled. If any such exceptions occur, execution is
aborted. Underflow results will be set to zero unless you
explicitly specify -no-ftz. On Itanium(R)-based systems,
underflow behavior is equivalent to specifying option -ftz. On
IA-32 or Intel(R) EM64T systems, underflow results from SSE
instructions, as well as x87 instructions, will be set to zero.
By contrast, option -ftz only sets SSE underflow results to
zero.
To get more detailed location information about where the error
occurred, use -traceback.
1 - All floating-point exceptions are disabled. Underflow
results will be set to zero unless you explicitly specify -no-
ftz.
3 - All floating-point exceptions are disabled. Floating-point
underflow is gradual, unless you explicitly specify a compiler
option that enables flush-to-zero. This is the default; it
provides full IEEE support. (Also see -ftz.)
-fpic (L*X only)
Generates position-independent code. On IA-32 systems and
Intel(R) EM64T systems, this option must be used when building
shared objects. This option can also be specified as -fPIC.
The default is -fno-pic.
-fp-model <keyword>
Controls the semantics of floating-point calculations. The fol-
lowing are -fp-model options:
· -fp-model precise
Enables value-safe optimizations on floating-point data and
rounds intermediate results to source-defined precision.
Disables optimizations that can change the result of float-
ing-point calculations, which is required for strict ANSI
conformance. These semantics ensure the accuracy of floating-
point computations, but they may slow performance.
Floating-point exception semantics are disabled by default.
This option is equivalent to -fp-model source.
· -fp-model fast[=1|2]
Enables more aggressive optimizations when implementing
floating-point calculations. These optimizations increase
speed, but may alter the accuracy of floating-point computa-
tions.
Specifying fast is the same as specifying fast=1. fast=2 may
produce faster and less accurate results.
Floating-point exception semantics are disabled by default
and they cannot be enabled.
· -fp-model strict
Enables precise and except. This is the strictest floating-
point model.
· -fp-model source
Enables value-safe optimizations on floating-point data and
rounds intermediate results to source-defined precision. This
option is equivalent to -fp-model precise.
· -fp-model [no-]except
Determines whether floating-point exception semantics are
used. Floating-point exception semantics are enabled if -fp-
model except is specified; they are disabled if -fp-model no-
except is specified.
The default is -fp-model fast=1. However, if you specify -O0,
the default is -fltconsistency.
The keywords can be considered in groups:
· Group A: source, precise, fast, strict
· Group B: except or no-except
You can use more than one keyword. However, the following rules
apply:
· You cannot specify fast and except together in the same com-
pilation. You can specify any other combination of group A
and group B.
Since fast is the default, you must not specify except with-
out a group A keyword.
· You should specify only one keyword from group A. If you try
to specify more than one keyword from group A, the last
(rightmost) one takes effect.
· If you specify except more than once, the last (rightmost)
one takes effect.
-fpp Runs the Fortran preprocessor on source files prior to compila-
tion.
-fpscomp [keyword]
Specifies the compatibility with Microsoft* Fortran PowerSta-
tion or Intel Fortran. The following are -fpscomp options:
· -fpscomp all
Specifies that all options should be used for Fortran Power-
Station compatibility. This is the same as specifying
-fpscomp with no keyword. The default is -fpscomp libs.
· -fpscomp filesfromcmd
Specifies that Fortran PowerStation behavior is used when the
OPEN file specifier is blank. The default is -fpscomp
nofilesfromcmd.
· -fpscomp general
Specifies that Fortran PowerStation semantics are used when
differences exist with Intel Fortran. The default is
-fpscomp nogeneral.
· -fpscomp ioformat
Specifies that Fortran PowerStation semantics and record for-
mat for list-directed formatted and unformatted I/O should be
used. The default is -fpscomp noioformat.
· -fpscomp ldio_spacing
Specifies that a blank should not be inserted after a numeric
value before a character value (undelimited character
string). This representation is used by Intel Fortran
releases before Version 8.0 and by Fortran PowerStation. If
you specify -fpscomp general, it sets -fpscomp ldio_spacing.
The default is -fpscomp noldio_spacing, which conforms to the
Fortran 95 standard by inserting a blank after a numeric
value before a character value.
· -fpscomp nolibs
Prevents the portability library from being passed to the
linker. The default is -fpscomp libs.
· -fpscomp logicals
Specifies that the integer values 1 and 0 are used to repre-
sent the LOGICAL values .TRUE. and .FALSE. respectively.
This representation is used by Intel Fortran releases before
Version 8.0 and by Fortran PowerStation.
The default is -fpscomp nologicals, which specifies that odd
integer values are treated as true and even integer values
are treated as false; specifically .TRUE. and .FALSE. are -1
and 0 respectively. This representation is used by Compaq
Visual Fortran.
· -fpscomp none
Specifies that no options should be used for Fortran Power-
Station compatibility. This is the same as specifying -nofp-
scomp.
-fpstkchk (i32 and i32em)
Generates extra code after every function call to ensure that
the FP (floating-point) stack is in the expected state. By
default, there is no checking. So when the FP stack overflows,
a NaN value is put into FP calculations, and the results of the
program differ. Unfortunately, the overflow point can be far
away from the point of the actual bug. The -fpstkchk option
places code that causes an access violation exception immedi-
ately after an incorrect call occurs, thus making it easier to
locate these issues.
-FR Specifies source files are in free format (same as the -free
option).
-fr32 (i64 only; L*X only)
Disables use of high floating-point registers. Uses only the
lower 32 floating-point registers.
-free Specifies source files are in free format. By default, source
file format is determined by the file suffix.
-fsource-asm
Produces an assembly file with optional source code annota-
tions. To use this option, you must also specify -S.
-fsyntax-only
Specifies that the source file should be checked only for cor-
rect syntax (same as the -syntax-only, -y, and -syntax
options).
-ftrapuv
Initializes stack local variables to an unusual value to aid
error detection. Normally, these local variables should be
initialized in the application.
The option sets any uninitialized local variables that are
allocated on the stack to a value that is typically interpreted
as a very large integer or an invalid address. References to
these variables are then likely to cause run-time errors that
can help you detect coding errors.
-ftz Flushes denormal results to zero when the application is in the
gradual underflow mode. It may improve performance if the
denormal values are not critical to the behavior of your
application. The default is -no-ftz.
The following options set the -ftz option: -fpe0, -fpe1, and on
Itanium(R)-based systems, option -O3. Option -O2 sets the -no-
ftz option.
Note: When SSE instructions are used on IA-32 systems, option
-no-ftz is ignored. However, you can enable gradual underflow
by calling a function in C in the main program that clears the
FTZ and DAZ bits in the MXCSR or by calling the function
for_set_fpe in the main program to clear those bits. Be aware
that denormal processing can significantly slow down computa-
tion.
-funroll-loops
Tells the compiler to use default heuristics to unroll loops.
This is the same as specifying -unroll.
-fverbose-asm
Produces an assembly file with compiler comments, including
options and version information. To use this option, you must
also specify -S, which sets -fverbose-asm. If you do not want
this default when you specify -S, specify -fnoverbose-asm.
-fvisibility=<keyword>
-fvisibility-<keyword>=<file>
The first form specifies the default visibility for global sym-
bols. The second form specifies the visibility for symbols
that are in a file (for symbols specified in <file>, this form
overrides the first form). <file> is the pathname of a file
containing the list of symbols whose visibility you want to
set; the symbols are separated by whitespace (spaces, tabs, or
newlines). <keyword> specifies the visibility setting; it can
be any of the following:
default - This setting means other components can reference the
symbol, and the symbol definition can be overridden (preempted)
by a definition of the same name in another component.
extern - This setting means the symbol is treated as though it
is defined in another component. It also means that the symbol
can be overridden by a definition of the same name in another
component. This setting only applies to functions.
hidden - This setting means other components cannot directly
reference the symbol. However, its address might be passed to
other components indirectly.
internal - This setting means the symbol cannot be referenced
outside its defining component, either directly or indirectly.
protected - This setting means other components can reference
the symbol, but it cannot be overridden by a definition of the
same name in another component.
If this option is specified more than once on the command line,
the last specification takes precedence over any others.
-g Produces symbolic debug information in the object file. The
compiler does not support the generation of debugging informa-
tion in assemblable files. If you specify the -g option, the
resulting object file will contain debugging information, but
the assemblable file will not.
On IA-32 systems, specifying the -g or -O0 option automatically
sets the -fp option.
-gen-interfaces
Tells the compiler to generate an interface block for each rou-
tine (that is, for each SUBROUTINE and FUNCTION statement)
defined in the source file.
The compiler generates two files for each routine, a .mod file
and a .f90 file, and places them in the current directory or in
the directory specified by the include ( -I ) or -module
option. The .f90 file is the text of the interface block; the
.mod file is the interface block compiled into binary form.
The default is -nogen-interfaces.
-help Displays the list of compiler options.
-I<dir>
Specifies a directory to add to the include path, which is used
to search for module files (USE statement) and include files
(INCLUDE statement).
-i-dynamic
Causes Intel-provided libraries to be linked in dynamically. It
is the opposite of -i-static.
-i-static
Causes Intel-provided libraries to be linked in statically. It
is the opposite of -i-dynamic.
-i2 Makes default integer and logical variables 2 bytes long (same
as the -integer_size 16 option). The default is -integer_size
32.
-i4 Makes default integer and logical variables 4 bytes long (same
as the -integer_size 32 option). This is the default.
-i8 Makes default integer and logical variables 8 bytes long (same
as the -integer_size 64 option). The default is -integer_size
32.
-implicitnone
Sets the default type of a variable to undefined (IMPLICIT
NONE). This is the same as specifying the -u option.
-inline-debug-info (L*X only)
Produces enhanced source position information for inlined code.
This leads to greater accuracy when reporting the source loca-
tion of any instruction. It also provides enhanced debug infor-
mation useful for function call traceback. To use this option
for debugging, you must also specify a debug enabling option,
such as -g.
-inline-factor=<n>
Specifies the percentage multiplier that should be applied to
all inlining options that define upper limits: -inline-max-
size, -inline-max-total-size, -inline-max-per-routine, and
-inline-max-per-compile.
This option takes the default value for each of the above
options and multiplies it by <n> divided by 100. For example,
if 200 is specified, all inlining options that define upper
limits are multiplied by a factor of 2.
<n> is a positive integer specifying the percentage value. The
default value is 100 (a factor of 1).
If you specify -no-inline-factor, the following occurs:
· Every function is considered to be a small or medium func-
tion; there are no large functions.
· There is no limit to the size a routine may grow when inline
expansion is performed.
· There is no limit to the number of times some routine may be
inlined into a particular routine.
· There is no limit to the number of times inlining can be
applied to a compilation unit.
-inline-forceinline
Specifies that an inline routine should be inlined whenever the
compiler can do so. This causes the routines marked with an
inline keyword or directive to be treated as if they were "for-
ceinline".
-inline-max-per-compile=<n>
Specifies the maximum number of times inlining may be applied
to an entire compilation unit. <n> is a positive integer that
specifies the maximum number.
For compilations using Interprocedural Optimizations (IPO), the
entire compilation is a compilation unit. For other compila-
tions, a compilation unit is a file.
If you specify -no-inline-max-per-compile, there is no limit to
the number of times inlining may be applied to a compilation
unit.
-inline-max-per-routine=<n>
Specifies the maximum number of times the inliner may inline
into a particular routine. <n> is a positive integer that spec-
ifies the maximum number.
If you specify -no-inline-max-per-routine, there is no limit to
the number of times some routine may be inlined into a particu-
lar routine.
-inline-max-size=<n>
Specifies the lower limit for the size of what the inliner con-
siders to be a large routine. It specifies the boundary between
what the inliner considers to be medium and large-size rou-
tines. <n> is a positive integer that specifies the minimum
size of a large routine.
The inliner prefers to inline small routines. It has a prefer-
ence against inlining large routines. So, any large routine is
highly unlikely to be inlined.
If you specify -no-inline-max-size, there are no large rou-
tines. Every routine is either a small or medium routine.
-inline-max-total-size=<n>
Specifies how much larger a routine can normally grow when
inline expansion is performed. It limits the potential size of
the routine. <n> is a positive integer that specifies the per-
mitted increase in the size of the routine.
If you specify -no-inline-max-total-size, there is no limit to
the size a routine may grow when inline expansion is performed.
-inline-min-size=<n>
Specifies the upper limit for the size of what the inliner con-
siders to be a small routine. It specifies the boundary between
what the inliner considers to be small and medium-size rou-
tines. <n> is a positive integer that specifies the maximum
size of a small routine.
The inliner has a preference to inline small routines. So, when
a routine is smaller than or equal to the specified size, it is
very likely to be inlined.
If you specify -no-inline-min-size, there is no limit to the
size of small routines. Every routine is a small routine; there
are no medium or large routines.
-intconstant
Tells the compiler to use Fortran 77 semantics, rather than
Fortran 95/90 semantics, to determine the KIND for integer
constants. The default is -nointconstant.
-integer_size <size>
Defines the size of INTEGER and LOGICAL variables. <size> can
be 16, 32, or 64. The default is -integer_size 32.
-ip Enables additional interprocedural optimizations for single
file compilation. One of these optimizations enables the com-
piler to perform inline function expansion for calls to func-
tions defined within the current source file.
-ip-no-inlining
Disables full and partial inlining enabled by -ip or -ipo.
-ip-no-pinlining (i32 and i32em)
Disables partial inlining. To use this option, you must specify
-ip or -ipo.
-IPF-flt-eval-method0 (i64 only; L*X only)
Tells the compiler to evaluate the expressions involving float-
ing-point operands in the precision indicated by the variable
types declared in the program. By default, intermediate float-
ing-point expressions are maintained in higher precision.
-IPF-fltacc (i64 only; L*X only)
Disables optimizations that affect floating-point accuracy. If
the default setting is used (-IPF-fltacc-), the compiler may
apply optimizations that reduce floating-point accuracy. You
can use -IPF-fltacc or -fltconsistency to improve floating-
point accuracy, but at the cost of disabling some optimiza-
tions.
-IPF_fp_relaxed (i64 only; L*X only)
Enables use of faster but slightly less accurate code sequences
for math functions, such as divide and sqrt. When compared to
strict IEEE* precision, this option slightly reduces the accu-
racy of floating-point calculations performed by these func-
tions, usually limited to the least significant digit.
This option also enables the performance of more aggressive
floating-point transformations, which may affect accuracy.
-IPF-fp-speculation<mode> (i64 only; L*X only)
Tells the compiler to speculate on floating-point (FP) opera-
tions in one of the following <mode>s:
fast - Speculate on floating-point operations. This is the
default.
safe - Speculate on floating-point operations only when safe.
strict - This is the same as specifying off.
off - Disables speculation of floating-point operations.
-ipo[n]
Enables multifile interprocedural (IP) optimizations (between
files). When you specify this option, the compiler performs
inline function expansion for calls to functions defined in
separate files.
n is an optional integer that specifies the number of object
files the compiler should create. Any integer greater than or
equal to 0 is valid.
If n is 0, the compiler decides whether to create one or more
object files based on an estimate of the size of the applica-
tion. It generates one object file for small applications, and
two or more object files for large applications.
If n is greater than 0, the compiler generates n object files,
unless n exceeds the number of source files (m), in which case
the compiler generates only m object files.
If you do not specify n, the default is 0.
-ipo-c Tells the compiler to generate a multifile object file
(ipo_out.o) that can be used in further link steps.
-ipo-S Tells the compiler to generate a multifile assembly file
(ipo_out.s) that can be used in further link steps.
-ipo-separate
Tells the compiler to generate one object file per source file.
This option overrides any -ipo[n] specification.
-isystem<dir>
Specifies a directory (dir) to add to the start of the system
include path. The compiler searches the specified directory
for include files after it searches all directories specified
by the -I compiler option but before it searches the standard
system directories. This option is provided for compatibility
with gcc.
-ivdep-parallel (i64 only; L*X only)
Tells the compiler that there is no loop-carried memory depen-
dency in any loop following an IVDEP directive.
-Kpic (L*X only)
This is a deprecated option; it can also be specified as -KPIC.
Use -fpic instead.
-L<dir>
Tells the linker to search for libraries in <dir> before
searching the standard directories.
-l<string>
Tells the linker to search for a specified library
(lib<string>) when linking.
Because the linker searches and processes libraries and object
files in the order they are specified, you should specify this
option following the last object file it applies to.
-logo Displays the compiler version information (same as the -V
option). The default is -nologo.
-lowercase
Causes the compiler to ignore case differences in identifiers
and to convert external names to lowercase (same as the -names
lowercase option). This is the default.
-map-opts (L*X only)
Maps one or more Linux compiler options to their equivalent on
a Windows system and outputs the result to stdout. The tool
can be invoked from the compiler command line or it can be used
directly. No compilation is performed when the option mapping
tool is used. Compiler options are mapped to their equivalent
on the architecture you are using.
-mcmodel=<mem_model> (i32em only; L*X only)
Tells the compiler to use a specific memory model to generate
code and store data. This option can affect code size and per-
formance.
You can specify one of the following values for <mem_model>:
· small
Restricts code and data to the first 2GB of address space.
All accesses of code and data can be done with Instruction
Pointer (IP)-relative addressing. This is the default.
· medium
Restricts code to the first 2GB; it places no memory restric-
tion on data. Accesses of code can be done with IP-relative
addressing, but accesses of data must be done with absolute
addressing.
· large
Places no memory restriction on code or data. All accesses of
code and data must be done with absolute addressing.
If your program has COMMON blocks and local data with a total
size smaller than 2GB, -mcmodel=small is sufficient. COMMONs
larger than 2GB require -mcmodel=medium or -mcmodel=large.
Allocation of memory larger than 2GB can be done with any set-
ting of -mcmodel.
IP-relative addressing requires only 32 bits, whereas absolute
addressing requires 64-bits. IP-relative addressing is some-
what faster. So, the small memory model has the least impact on
performance.
Note: When the medium or large memory models are specified, you
must also specify option -i-dynamic to ensure that the correct
dynamic versions of the Intel run-time libraries are used.
When shared objects (.so files) are built, Position-Independent
Code (PIC) is specified so that a single .so file can support
all three memory models. The compiler driver adds option -fpic
to implement the PIC.
However, you must specify a memory model for code that is to be
placed in a static library or code that will be linked stati-
cally.
-mieee-fp
Enables improved floating-point consistency. Floating-point
operations are not reordered and the result of each floating-
point operation is stored in the target variable rather than
being kept in the floating-point processor for use in a subse-
quent calculation. This is the same as specifying -fltconsis-
tency or -mp.
The default, -mno-ieee-fp, provides better accuracy and run-
time performance at the expense of less consistent floating-
point results.
-mixed_str_len_arg
Tells the compiler that the hidden length passed for a charac-
ter argument is to be placed immediately after its correspond-
ing character argument in the argument list. The default is
-nomixed_str_len_arg, which places the hidden lengths in
sequential order at the end of the argument list.
-module <dir>
Specifies the directory <dir> where module (.mod) files should
be placed when created and where they should be searched for
(USE statement).
-mp Maintains floating-point precision (while disabling some opti-
mizations). The -mp option restricts optimization to maintain
declared precision and to ensure that floating-point arithmetic
conforms more closely to the ANSI* and IEEE standards. This is
the same as specifying -fltconsistency or -mieee-fp.
For most programs, specifying this option adversely affects
performance. If you are not sure whether your application needs
this option, try compiling and running your program both with
and without it to evaluate the effects on both performance and
precision.
-mp1 Improves floating-point precision and consistency. This option
disables fewer optimizations and has less impact on performance
than -fltconsistency or -mp.
-mrelax (i64 only; L*X only)
Tells the compiler to pass linker option -relax to the linker.
The default is -mno-relax.
-mtune=<processor>
Performs optimizations for a specified CPU.
On IA-32 systems, you can specify one of the following values
for <processor>:
· pentium
Optimizes for Intel(R) Pentium(R) processors.
· pentiumpro
Optimizes for Intel(R) Pentium(R) Pro, Intel Pentium II, and
Intel Pentium III processors.
· pentium4
Optimizes for Intel Pentium 4 processors. This is the
default.
· pentium-mmx
Optimizes for Intel(R) Pentium(R) with MMX(TM) technology.
On Itanium(R)-based Linux systems, you can specify one of the
following values for <processor>:
· itanium
Optimizes for Intel(R) Itanium(R) processors.
· itanium2
Optimizes for Intel(R) Itanium(R) 2 processors. This is the
default.
· itanium2-p9000
Optimizes for Dual-Core Intel(R) Itanium(R) 2 Processor 9000
Sequence processors. This option affects the order of the
generated instructions, but the generated instructions are
limited to Intel(R) Itanium(R) 2 processor instructions
unless the program uses (executes) intrinsics specific to the
Dual-Core Intel(R) Itanium(R) 2 Processor 9000 Sequence pro-
cessors.
-names <keyword>
Specifies how source code identifiers and external names are
interpreted. The following are -names options:
· -names as_is
Causes the compiler to distinguish case differences in iden-
tifiers and to preserve the case of external names.
· -names lowercase
Causes the compiler to ignore case differences in identifiers
and to convert external names to lowercase. This is the
default.
· -names uppercase
Causes the compiler to ignore case differences in identifiers
and to convert external names to uppercase.
-nbs Tells the compiler to treat a backslash (\) as a normal charac-
ter in character literals, not an escape character (same as the
-assume nobscc option). This is the default.
-no-ansi-alias
Tells the compiler to assume the program does not adhere to the
Fortran 95 Standard type aliasability rules. The default is
-ansi-alias, which tells the compiler to assume that the
program adheres to these aliasability rules.
-no-cpprt
Tells the compiler to use the default run-time libraries and
not link to any additional C++ run-time libraries. This is the
same as specifying -no-cxxlib.
-no-fp-port (i32 and i32em)
Tells the compiler to keep results of floating-point operations
in higher precision. This provides better performance but less
consistent floating-point results. The default is -fp-port,
which rounds floating-point results after floating-point opera-
tions so rounding to user-declared precision occurs at assign-
ments and type conversions. This has some impact on speed.
-no-global-hoist
Disables certain optimizations, such as load hoisting and spec-
ulative loads, that can move memory loads to a point earlier in
the program execution than where they appear in the source.
This option is useful for some applications, such as those that
use shared or dynamically mapped memory, which can fail if a
load is moved too early in the execution stream (for example,
before the memory is mapped).
In most cases, these optimizations are safe and can improve
performance. The default, -global-hoist, enables these opti-
mizations.
-no-IPF-fma (i64 only; L*X only)
Disables the combining of floating-point multiplies and
add/subtract operations. It also disables the contraction of
floating-point multiply and add/subtract operations into a sin-
gle operation. The default is -IPF-fma, which tells the com-
piler to combine and contract these operations whenever possi-
ble. However, if you specify -mp and do not explicitly specify
-IPF-fma, the default is -no-IPF-fma.
-no-prec-div (i32 and i32em)
Enables optimizations that give slightly less precise results
than full IEEE division. With some optimizations, such as -xN
and -xB, the compiler may change floating-point division compu-
tations into multiplication by the reciprocal of the denomina-
tor. For example, A/B is computed as A * (1/B) to improve the
speed of the computation.
The default is -prec-div, which provides fully precise IEEE
division. It improves precision of floating-point divides by
disabling floating-point division-to-multiplication optimiza-
tions, resulting in greater accuracy with some loss of perfor-
mance.
-no-prefetch (i64 only; L*X only)
Disables prefetch insertion optimization. To use this option,
you must also specify -O3. The default is -prefetch.
-noalign
Prevents the alignment of data items. This is the same as spec-
ifying -align none. The default is -align.
-noaltparam
Specifies that the alternate form of parameter constant decla-
rations (without parentheses) should not be recognized (same as
the -nodps option). This form has no parentheses surrounding
the list, and the form of the constant, rather than implicit or
explicit typing, determines the data type of the variable. The
default is -altparam.
-nobss-init
Places any variables that are explicitly initialized with zeros
in the DATA section. By default, variables explicitly initial-
ized with zeros are placed in the BSS section.
-nodefaultlibs
Prevents the compiler from using standard libraries when link-
ing.
-nodefine
Specifies that all preprocessor definitions apply only to -fpp
and not to Intel Fortran conditional compilation directives.
This is the same as specifying -noD.
-nodps Specifies that the alternate form of parameter constant decla-
rations (without parentheses) should not be recognized (same as
the -noaltparam option). The default is -dps.
-nofor_main
Specifies the main program is not written in Fortran, and pre-
vents the compiler from linking for_main.o into applications.
The default is -for_main.
-noinclude
Prevents the compiler from searching in /usr/include for files
specified in an INCLUDE statement. You can specify the -I<dir>
option along with this option. This option does not affect the
fpp preprocessor behavior, and is not related to the Fortran
95/90 USE statement.
-nostartfiles
Prevents the compiler from using standard startup files when
linking.
-nostdinc
Removes standard directories from the include file search path
(same as the -X option).
-nostdlib
Prevents the compiler from using standard libraries and startup
files when linking.
-nus Prevents the compiler from appending an underscore character to
external user-defined names. This option is the same as the
-assume nounderscore option, and is the opposite of -us.
-o <file>
Specifies the name (<file>) for an output file as follows:
· If -c is specified, it specifies the name of the generated
object file.
· If -S is specified, it specifies the name of the generated
assembly listing file.
· If -preprocess_only or -P is specified, it specifies the name
of the generated preprocessor file.
Otherwise, -o specifies the name of the executable file.
-O0 Disables all -O<n> optimizations. On IA-32 and Intel(R) EM64T
systems, this option sets the -fp option.
-O1 On IA-32 and Intel(R) EM64T systems, enables optimizations for
speed. Also disables intrinsic recognition and the -fp option.
This option is the same as the -O2 option.
On Itanium(R)-based systems, the -O1 option enables optimiza-
tions for server applications (straight-line and branch-like
code with a flat profile). Enables optimizations for speed,
while being aware of code size. For example, this option dis-
ables software pipelining and loop unrolling.
-O2 or -O
This option is the default for optimizations. However, if -g
is specified, the default is -O0.
On Itanium(R)-based systems, the -O2 option enables optimiza-
tions for speed, including global code scheduling, software
pipelining, predication, and speculation. It also enables:
· Inlining of intrinsics
· Intra-file interprocedural optimizations, which include:
inlining, constant propagation, forward substitution, routine
attribute propagation, variable address-taken analysis, dead
static function elimination, and removal of unreferenced
variables.
· The following capabilities for performance gain: constant
propagation, copy propagation, dead-code elimination, global
register allocation, global instruction scheduling and con-
trol speculation, loop unrolling, optimized code selection,
partial redundancy elimination, strength reduction/induction
variable simplification, variable renaming, exception han-
dling optimizations, tail recursions, peephole optimizations,
structure assignment lowering and optimizations, and dead
store elimination.
-O3 Enables -O2 optimizations plus more aggressive optimizations,
such as prefetching, scalar replacement, and loop transforma-
tions. Enables optimizations for maximum speed, but does not
guarantee higher performance unless loop and memory access
transformations take place.
On IA-32 and Intel(R) EM64T systems, when the -O3 option is
used with the -ax and -x options, it causes the compiler to
perform more aggressive data dependency analysis than for -O2,
which may result in longer compilation times.
On Itanium(R)-based systems, the -O3 option enables optimiza-
tions for technical computing applications (loop-intensive
code): loop optimizations and data prefetch.
-Ob<n> Specifies the level of inline function expansion. You can
specify one of the following values for <n>:
0 - Disables inlining of user-defined functions. However,
statement functions are always inlined. This is the default if
-O0 is specified.
1 - Enables inlining when an inline keyword or an inline direc-
tive is specified.
2 - Enables inlining of any function at the discretion of the
compiler. This is the default if option -O2 is specified or is
in effect by default.
-onetrip
Tells the compiler to execute at least one iteration of DO
loops (same as the -1 option). This option has the same effect
as -f66.
-openmp
Enables the parallelizer to generate multithreaded code based
on OpenMP* directives. The code can be executed in parallel on
both uniprocessor and multiprocessor systems. The -openmp
option works with both -O0 (no optimization) and any optimiza-
tion level of -O<n>. Specifying -O0 with -openmp helps to debug
OpenMP applications.
-openmp-profile (L*X only)
Enables analysis of OpenMP* applications. To use this option,
you must have Intel(R) Thread Profiler installed, which is one
of the Intel(R) Threading Tools. If this threading tool is not
installed, this option has no effect.
-openmp-report[n]
Controls the level of diagnostic messages of the OpenMP paral-
lelizer. You can specify one of the following values for [n]:
0 - Displays no diagnostic information.
1 - Displays diagnostics indicating loops, regions, and sec-
tions successfully parallelized. This is the default.
2 - Displays the diagnostics specified by -openmp-report1 plus
diagnostics indicating successful handling of MASTER con-
structs, SINGLE constructs, CRITICAL constructs, ORDERED con-
structs, ATOMIC directives, etc.
-openmp-stubs
Enables compilation of OpenMP programs in sequential mode. The
OpenMP directives are ignored and a stub OpenMP library is
linked.
-opt-mem-bandwidth<n> (i64 only; L*X only)
Enables performance tuning and heuristics that control memory
bandwidth use among processors. It allows the compiler to be
less aggressive with optimizations that might consume more
bandwidth, so that the bandwidth can be well-shared among mul-
tiple processors for a parallel program.
For values of <n> greater than 0, the option tells the compiler
to enable a set of performance tuning and heuristics in com-
piler optimizations such as prefetching, privatization, aggres-
sive code motion, and so forth, for reducing memory bandwidth
pressure and balancing memory bandwidth traffic among threads.
<n> is the level of optimizing for memory bandwidth usage. You
can specify one of the following values for <n>:
0 - Enables a set of performance tuning and heuristics in com-
piler optimizations that is optimal for serial code. This is
the default for serial code.
1 - Enables a set of performance tuning and heuristics in com-
piler optimizations for multithreaded code generated by the
compiler. This is the default if compiler option -parallel or
-openmp is specified, or Cluster OpenMP option -cluster-openmp
is specified (see the Cluster OpenMP documentation).
2 - Enables a set of performance tuning and heuristics in com-
piler optimizations for parallel code such as Windows Threads,
pthreads, and MPI code, besides multithreaded code generated by
the compiler.
-opt-report
Tells the compiler to generate an optimization report to
stderr.
-opt-report-file<file>
Tells the compiler to generate an optimization report named
<file>.
-opt-report-help
Displays the logical names of optimizer phases available for
report generation (using -opt-report-phase).
-opt-report-level[level]
Specifies the detail level of the optimization report. [level]
can be min, med, or max. The default is -opt-report-levelmin.
-opt-report-phase<phase>
Specifies the optimizer phase (<phase>) to generate reports
for. This option can be used multiple times on the same com-
mand line to generate reports for multiple optimizer phases.
Currently, the following optimizer phases are supported:
ipo - Interprocedural Optimizer
hlo - High Level Optimizer
ilo - Intermediate Language Scalar Optimizer
ecg - Code Generator (Itanium(R)-based systems only; Linux sys-
tems only)
ecg_swp - Software pipelining component of the Code Generator
(Itanium(R)-based systems only; Linux systems only)
pgo - Profile Guided Optimization
all - All phases
When one of these logical names for optimizer phases is speci-
fied for <phase>, all reports from that optimizer phase are
generated.
To use this option, you must also specify option -opt-report.
-opt-report-routine[string]
Generates a report on the routines containing the specified
<string> as part of their name. If <string> is not specified,
reports from all routines are generated.
-p Compiles and links for function profiling with gprof(1). This
is the same as specifying -pg or -qp, except that -pg is not
available on Itanium(R)-based systems.
-P Causes the Fortran preprocessor to send output to a file (same
as the -preprocess_only and -F options). Note that the source
file is not compiled.
-pad Enables the changing of the variable and array memory layout.
The default is -nopad.
-pad-source
Specifies that fixed-form source records shorter than the
statement field width are to be padded with spaces (on the
right) to the end of the statement field. This affects the
interpretation of character and Hollerith literals that are
continued across source records. The default is -nopad-source.
-par-report[n]
Controls the level of diagnostic messages of the auto-paral-
lelizer. You can specify one of the following values for [n]:
0 - Displays no diagnostic information.
1 - Displays diagnostics indicating loops successfully auto-
parallelized. This is the default. Issues a "LOOP AUTO-PARAL-
LELIZED" message for parallel loops.
2 - Displays diagnostics indicating loops successfully auto-
parallelized, as well as unsuccessful loops.
3 - Displays the diagnostics specified by -par-report2 plus
additional information about any proven or assumed dependencies
inhibiting auto-parallelization (reasons for not paralleliz-
ing).
-par-threshold[n]
Sets a threshold for the auto-parallelization of loops based on
the probability of profitable execution of the loop in paral-
lel. This option is used for loops whose computation work vol-
ume cannot be determined at compile-time. The threshold is usu-
ally relevant when the loop trip count is unknown at compile-
time.
[n] is an integer from 0 to 100. The default value is 100.
The compiler applies a heuristic that tries to balance the
overhead of creating multiple threads versus the amount of work
available to be shared amongst the threads.
-parallel
Tells the auto-parallelizer to generate multithreaded code for
loops that can be safely executed in parallel. To use this
option, you must also specify -O2 or -O3.
-pc<n> (i32 and i32em)
Enables control of floating-point significand precision. Some
floating-point algorithms are sensitive to the accuracy of the
significand, or fractional part of the floating-point value.
For example, iterative operations like division and finding the
square root can run faster if you lower the precision with the
-pc<n> option. You can specify one of the following values for
<n>:
32 - Rounds the significand to 24 bits (single precision). Note
that a change of the default precision control or rounding mode
(for example, by using the -pc32 option or by user interven-
tion) may affect the results returned by some of the mathemati-
cal functions.
64 - Rounds the significand to 53 bits (double precision).
80 - Rounds the significand to 64 bits (extended precision).
This is the default.
-pg (i32 and i32em)
Compiles and links for function profiling with gprof(1). This
is the same as specifying -p or -qp, except that they are also
available on Itanium(R)-based systems.
-prec-sqrt (i32 and i32em)
Improves precision of square root implementations; it has some
speed impact. This option inhibits any optimizations that can
adversely affect the precision of a square root computation.
The result is fully precise square root implementations, with
some loss of performance. This is the default setting if you
specify -O0, -mp, or -mp1.
-preprocess_only
Causes the Fortran preprocessor to send output to a file (same
as the -F and -P options). Note that the source file is not
compiled.
-print-multi-lib
Prints information about where system libraries should be
found, but no compilation occurs. It is provided for compati-
bility with gcc.
-prof-dir <dir>
Specifies a directory (<dir>) for profiling output files (*.dyn
and *.dpi).
-prof-file <file>
Specifies a file name (<file>) for the profiling summary file.
-prof-format-32 (i32 and i64; L*X only)
Produces profile data with 32-bit counters; this option allows
compatibility with earlier compilers. The default is to pro-
duce profile data with 64-bit counters to handle large numbers
of events.
-prof-gen
Instruments a program for profiling.
-prof-gen-sampling (i32 only; L*X only)
Prepares application executables for hardware profiling (sam-
pling) and causes the compiler to generate source code mapping
information.
-prof-genx
Instruments a program for profiling and gathers extra informa-
tion for code coverage tools.
-prof-use
Enables use of profiling information during optimization.
-Qinstall <dir>
Specifies the root directory (<dir>)where the compiler instal-
lation was performed. This option is useful if you want to use
a different compiler or if you did not use the ifortvars shell
script to set your environment variables.
-Qlocation,<string>,<dir>
Sets <dir> as the location of the tool specified by <string>.
-Qoption,<string>,<opts>
Passes options <opts> to the tool specified by <string>.
-qp Compiles and links for function profiling with gprof(1). This
is the same as specifying -p or -pg, except that -pg is not
available on Itanium(R)-based systems.
-r8 Makes default real and complex variables 8 bytes long. REAL
declarations are treated as DOUBLE PRECISION (REAL(KIND=8)) and
COMPLEX declarations are treated as DOUBLE COMPLEX (COM-
PLEX(KIND=8)). This option is the same as specifying -real_size
64 or -autodouble.
-r16 Makes default real and complex variables 16 bytes long. REAL
declarations are treated as extended precision REAL
(REAL(KIND=16); COMPLEX and DOUBLE COMPLEX declarations are
treated as extended precision COMPLEX (COMPLEX(KIND=16)). This
option is the same as specifying -real_size 128.
-rcd (i32 and i32em)
Enables fast float-to-integer conversions. This option can
improve the performance of code that requires floating-point-
to-integer conversions. The system default floating-point
rounding mode is round-to-nearest. However, the Fortran lan-
guage requires floating-point values to be truncated when a
conversion to an integer is involved. To do this, the compiler
must change the rounding mode to truncation before each float-
ing-point-to-integer conversion and change it back afterwards.
The -rcd option disables the change to truncation of the round-
ing mode for all floating-point calculations, including float-
ing point-to-integer conversions. This option can improve per-
formance, but floating-point conversions to integer will not
conform to Fortran semantics.
-real_size <size>
Defines the size of REAL and COMPLEX declarations, constants,
functions, and intrinsics. <size> can be 32, 64, or 128. The
default is -real_size 32.
-recursive
Specifies that all routines should be compiled for possible
recursive execution. This option sets the -auto option. The
default is -norecursive.
-reentrancy [keyword]
Specifies that the compiler should generate reentrant code that
supports a multithreaded application. The following are -reen-
trancy options:
· -reentrancy async
Tells the run-time library (RTL) that the program may contain
asynchronous (AST) handlers that could call the RTL. This
causes the RTL to guard against AST interrupts inside its own
critical regions.
· -reentrancy none
Tells the run-time library (RTL) that the program does not
rely on threaded or asynchronous reentrancy. The RTL will
not guard against such interrupts inside its own critical
regions. This is the default. This option is the same as
the -noreentrancy option.
· -reentrancy threaded
Tells the run-time library (RTL) that the program is multi-
threaded, such as programs using the POSIX threads library.
This causes the RTL to use thread locking to guard its own
critical regions. If you do not specify a keyword for -reen-
trancy, it is the same as specifying -reentrancy threaded.
-S Causes the compiler to compile to an assembly file (.s) only
and not link.
-safe-cray-ptr
Specifies that Cray pointers do not alias other variables.
-save Places variables, except those declared as AUTOMATIC, in static
memory (same as -noauto or -noautomatic). The default is -auto-
scalar. However, if you specify -recursive or -openmp, the
default is -automatic.
-scalar-rep (i32 only)
Enables scalar replacement performed during loop transforma-
tion. To use this option, you must also specify -O3. The
default is -no-scalar-rep.
-shared (L*X only)
Tells the compiler to produce a dynamic shared object instead
of an executable.
On IA-32 systems and Intel(R) EM64T systems, you must specify
-fpic for the compilation of each object file you want to
include in the shared library.
-shared-libcxa (L*X only)
Links the Intel libcxa C++ library dynamically, overriding the
default behavior when -static is used. This option is the
opposite of -static-libcxa.
-sox Tells the compiler to save the compiler options and version
number in the executable. The default is -no-sox.
-ssp (i32 only; L*X only)
Enables Software-based Speculative Pre-computation (SSP), which
is also called Helper-Threading optimization. It provides a way
to dynamically prefetch data cache blocks to counterbalance
ever-increasing memory latency. It exploits the properties of
source code constructs (such as delinquent loads and pointer-
chasing loops) in applications.
-stand [keyword]
Causes the compiler to issue compile-time messages for nonstan-
dard language elements. The following are -stand options:
· -stand f90
Causes the compiler to issue messages for language elements
that are not standard in Fortran 90 (same as the -std90
option).
· -stand f95
Causes the compiler to issue messages for language elements
that are not standard in Fortran 95 (same as the -std95 or
-std options). This option is set if you specify -warn stder-
rors. If you do not specify a keyword for -stand, it is the
same as specifying -stand 95.
· -stand none
Causes the compiler to issue no messages for nonstandard lan-
guage elements. This is the same as specifying -nostand.
This is the default.
-static (L*X only)
Prevents linking with shared libraries. Causes the executable
to link all libraries statically.
-static-libcxa (L*X only)
Links the Intel libcxa C++ library statically. This option is
the opposite of -shared-libcxa.
-std90 Causes the compiler to issue messages for language elements
that are not standard in Fortran 90 (same as the -stand f90
option).
-std95 or -std
Causes the compiler to issue messages for language elements
that are not standard in Fortran 95 (same as the -stand f95
option). This option is set if you specify -warn stderrors.
-syntax-only
Specifies that the source file should be checked only for cor-
rect syntax (same as the -fsyntax-only, -y, and -syntax
options). No code is generated, no object file is produced, and
some error checking done by the optimizer is bypassed. This
option lets you do a quick syntax check of your source file.
-T <file> (L*X only)
Tells the linker to read link commands from the specified
<file>.
-tcheck (L*X only)
Enables analysis of threaded applications. To use this option,
you must have Intel(R) Thread Checker installed, which is one
of the Intel(R) Threading Tools.
-Tf <file>
Specifies that <file> should be compiled as a Fortran source
file. This option is useful when you have a file with a non-
standard filename suffix.
This option assumes the file specified uses fixed source form.
If the file uses free source form, you must also specify option
-free.
-threads
Specifies that multithreaded libraries should be linked. This
is the default on Intel(R) EM64T systems. This option sets the
-reentrancy threaded option. On IA-32 and Intel(R) Itanium(R)
systems, the default is -nothreads.
-tpp1 (i64 only; L*X only)
Optimizes for the Intel(R) Itanium(R) processor.
-tpp2 (i64 only; L*X only)
Optimizes for the Intel(R) Itanium(R) 2 processor. This is the
default on Itanium(R)-based systems.
-tpp5 (i32 only; L*X only)
Optimizes for the Intel(R) Pentium(R) processor.
-tpp6 (i32 only; L*X only)
Optimizes for the Intel(R) Pentium(R) Pro, Intel(R) Pentium(R)
II and Intel(R) Pentium(R) III processors.
-tpp7 (i32 and i32em; L*X only)
Optimizes for the Intel(R) Core(TM) Duo processors, Intel(R)
Core(TM) Solo processors, Intel(R) Pentium(R) 4 processors,
Intel(R) Xeon(R) processors, Intel Pentium M processors, and
Intel Pentium 4 processors with Streaming SIMD Extensions 3
(SSE3) instruction support. This is the default on IA-32 sys-
tems and Intel(R) EM64T systems.
-traceback
Tells the compiler to generate extra information in the object
file to allow the display of source file traceback information
at run time when a severe error occurs. The default is
-notraceback.
-tune <keyword> (i32 and i32em)
Determines the version of the architecture for which the com-
piler generates instructions. The following are -tune options:
· -tune pn1
Optimizes for the Intel(R) Pentium(R) processor.
· -tune pn2
Optimizes for the Intel(R) Pentium(R) Pro, Intel(R) Pen-
tium(R) II, and Intel(R) Pentium(R) III processors.
· -tune pn3
Optimizes for the Intel(R) Pentium(R) Pro, Intel(R) Pen-
tium(R) II, and Intel(R) Pentium(R) III processors. This is
the same as specifying the -tune pn2 option.
· -tune pn4
Optimizes for the Intel(R) Pentium(R) 4 processor. This is
the default.
The only option available on Intel(R) EM64T systems is -tune
pn4.
-u Sets the default type of a variable to undefined (IMPLICIT
NONE). This is the same as specifying the -implicitnone
option.
-U<name>
Removes the predefined macro named <name>.
-unroll[n]
Sets the maximum number of times to unroll loops. Use -unroll0
to disable loop unrolling. The default is -unroll, which tells
the compiler to use default heuristics. This is the same as
specifying -funroll-loops.
-uppercase
Causes the compiler to ignore case differences in identifiers
and to convert external names to uppercase (same as the -names
uppercase option). The default is -lowercase (or -names lower-
case).
-us Tells the compiler to append an underscore character to exter-
nal user-defined names (opposite of -nus). Specifying -us is
the same as specifying the -assume underscore option.
-use-asm
Tells the compiler to produce objects through the assembler.
-v Tells the driver that tool commands should be shown and exe-
cuted. See also -dryrun.
-V Displays the compiler version information (same as the -logo
option).
-vec-report[n] (i32 and i32em)
Specifies the amount of vectorizer diagnostic information to
report. You can specify one of the following values for [n]:
0 - Produces no diagnostic information.
1 - Indicates vectorized loops. This is the default.
2 - Indicates vectorized and non-vectorized loops.
3 - Indicates vectorized and non-vectorized loops and prohibit-
ing data dependence information.
4 - Indicates non-vectorized loops.
5 - Indicates non-vectorized loops and prohibiting data depen-
dence information.
-vms Causes the run-time system to behave like HP* Fortran on Open-
VMS* Alpha systems and VAX* systems (VAX FORTRAN*) in the fol-
lowing ways:
· Modifies certain defaults
The -vms option sets the -check format and -check output_con-
version options. You can override this by specifying the
option on the command line. For example, if you specify -vms
-check noformat, you get -check noformat.
· Alignment
The -vms option does not affect the alignment of fields in
records or items in COMMON. Use -align norecords to pack
fields of records on the next byte boundary for compatibility
with HP Fortran on OpenVMS systems.
· INCLUDE qualifiers
/LIST and /NOLIST are recognized at the end of the file path-
name in an INCLUDE statement at compile time.
If the file name in the INCLUDE statement does not specify
the complete path, the path used is the current directory.
· Quotation mark character (")
A quotation mark is recognized as starting an octal constant
(such as "177) instead of a character literal ("...").
· Deleted records in relative files
When a record in a relative file is deleted, the first byte
of that record is set to a known character (currently '@').
Attempts to read that record later result in ATTACCNON
errors. The rest of the record (the whole record, if -vms is
not specified) is set to nulls for unformatted files and
spaces for formatted files.
· ENDFILE records
When an ENDFILE is performed on a sequential unit, an actual
one byte record containing a Ctrl/Z is written to the file.
If -vms is not specified, an internal ENDFILE flag is set and
the file is truncated.
The -vms option does not affect ENDFILE on relative files;
such files are truncated.
· Reading deleted records and ENDFILE records
The run-time direct access READ routine checks the first byte
of the retrieved record. If this byte is '@' or NULL ("\0"),
then ATTACCNON is returned.
The run-time sequential access READ routine checks to see if
the record it just read is one byte long and contains a
Ctrl/Z. If this is true, it returns EOF.
· OPEN statement effects
Carriage control defaults to FORTRAN if the file is format-
ted, and the unit is connected to a terminal (checked by
means of isatty(3)). Otherwise, carriage control defaults to
LIST.
The -vms option affects the record length for direct access
and relative organization files. The buffer size is
increased by one (to accommodate the deleted record charac-
ter).
· Implied logical unit numbers
Certain environment variables are recognized at run time for
ACCEPT, PRINT, and TYPE statements, and for READ and WRITE
statements that do not specify a unit number, such as: READ
(*,1000).
· Treatment of blanks in input
The -vms option causes the defaults for keyword BLANK in OPEN
statements to become 'NULL' for an explicit OPEN, and 'ZERO'
for an implicit OPEN of an external or internal file.
· Carriage control default
If -vms -ccdefault default is specified, carriage control
defaults to FORTRAN if the file is formatted and the unit is
connected to a terminal.
-w Disables all warning messages (same as the -nowarn and -warn
nogeneral options).
-W<n> Disables warnings (n=0) or enables warnings (n=1). The default
is -W1 (same as the -warn general option). -W0 is the same as
specifying -warn nogeneral, -nowarn, or -w.
-Wa,<o1>[,<o2>,...]
Passes options <o1>, <o2>, and so forth, to the assembler for
processing. If the assembler is not invoked, these options are
ignored.
-warn [keyword]
Specifies the level of diagnostic messages issued by the com-
piler. The following are -warn options:
· -warn all
Enables all warning messages. This is the same as specifying
-warn with no keyword.
· -warn none
Disables all warning messages. This is the same as specify-
ing -nowarn.
· -warn noalignments
Disables warnings for data that is not naturally aligned.
The default is -warn alignments.
· -warn declarations
Enables error messages about any undeclared symbols. This
option makes the default data type of a variable undefined
(IMPLICIT NONE) rather than using the implicit Fortran rules.
The default is -warn nodeclarations.
· -warn errors
Tells the compiler to change all warning-level messages into
error-level messages. The default is -warn noerrors.
· -warn nogeneral
Disables all information-level and warning-level messages.
The default is -warn general.
· -warn ignore_loc
Enables warnings when %LOC is stripped from an argument. The
default is -warn noignore_loc.
· -warn interfaces
Tells the compiler to check the interfaces of all SUBROUTINEs
called and FUNCTIONs invoked in your compilation against a
set of interface blocks stored separately from the source
being compiled.
The compiler generates a compile-time message if the inter-
face used to invoke a routine does not match the interface
defined in a .mod file external to the source (that is, in a
.mod generated by -gen-interfaces as opposed to a .mod file
USEd in the source). The compiler looks for these .mods in
the current directory or in the directory specified by the
include ( -I ) or -module option. The default is -warn noin-
terfaces.
· -warn stderrors
Tells the compiler to change warnings about Fortran standards
violations into error messages. This option sets the -std95
option. If you want Fortran 90 standards violations to
become errors, you should specify -warn stderrors and -std90.
The default is -warn nostderrors.
· -warn truncated_source
Enables warnings when source exceeds the maximum columm width
in fixed-format source files. The default is -warn notrun-
cated_source.
· -warn uncalled
Enables warnings when a statement function is never called.
The default is -warn nouncalled.
· -warn unused
Enables warnings about variables that are declared but never
used. The default is -warn nounused.
· -warn nousage
Disables warnings about questionable programming practices.
The default is -warn usage.
-watch [keyword]
Tells the compiler to display certain information to the con-
sole output window. The following are -watch options:
· -watch all
Enables all -watch options. This is the same as specifying
-watch with no keyword.
· -watch cmd
Tells the compiler to display and execute driver tool com-
mands. The default is -watch nocmd.
· -watch source
Tells the compiler to display the name of the file being com-
piled. The default is -watch nosource.
· -watch none
Disables all -watch options. This is the default. This is
the same as specifying -nowatch.
-WB Turns a compile-time bounds check into a warning. Normally,
compile-time bounds checks are errors.
-what Displays the version strings of the Fortran command and the
compiler.
-Wl,<o1>[,<o2>,...]
Passes options <o1>, <o2>, and so forth, to the linker for pro-
cessing. If the linker is not invoked, these options are
ignored.
-Wp,<o1>[,<o2>,...]
Passes options <o1>, <o2>, and so forth, to the preprocessor.
If the preprocessor is not invoked, these options are ignored.
-X Removes standard directories from the include file search path
(same as the -nostdinc option). You can use the -X option with
the -I option to prevent the compiler from searching the
default path for include files and direct it to use an alter-
nate path.
-x<p> (i32 and i32em)
Generates specialized and optimized code for the processor that
executes your program. The characters K, W, N, B, and P denote
the processor types (<p>). The following are -x options:
· -xK
Generates code for Intel Pentium III processors and compati-
ble Intel processors.
· -xW
Generates code for Intel Pentium 4 processors and compatible
Intel processors.
· -xN
Generates code for Intel Pentium 4 and compatible Intel pro-
cessors with Streaming SIMD Extensions 2. The resulting code
may contain unconditional use of features that are not sup-
ported on other processors.
This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced
data layout and code restructuring optimizations to improve
memory accesses for Intel processors.
· -xB
Generates code for Intel Pentium M processors and compatible
Intel processors. Also enables new optimizations in addition
to Intel processor-specific optimizations.
· -xP
Generates code for Intel(R) Core(TM) Duo processors, Intel(R)
Core(TM) Solo processors, Intel(R) Pentium(R) 4 processors
with Streaming SIMD Extensions 3, and compatible Intel pro-
cessors with Streaming SIMD Extensions 3. The resulting code
may contain unconditional use of features that are not sup-
ported on other processors.
This option also enables new optimizations in addition to
Intel processor-specific optimizations including advanced
data layout and code restructuring optimizations to improve
memory accesses for Intel processors.
The only options available on Intel(R) EM64T systems are -xW
and -xP.
On Mac OS systems, the only valid option is -xP. On these sys-
tems, it is the default and is always set.
If you specify more than one processor value, code is generated
for only the highest-performing processor specified. The high-
est-performing to lowest-performing processor values are: P, B,
N, W, K.
Do not use these options if you are executing a program on a
processor that is not an Intel(R) processor. If you use these
options on a non-compatible processor to compile the main pro-
gram, the program may fail with an illegal instruction excep-
tion or display other unexpected behavior.
In particular, such programs compiled with processor values N,
B, or P will display a fatal run-time error if they are exe-
cuted on unsupported processors. For more information, see your
Optimizing Applications guide.
-Xlinker <value>
Passes <value> directly to the linker for processing.
-y Specifies that the source file should be checked only for cor-
rect syntax (same as the -syntax-only, -fsyntax-only, and
-syntax options).
-zero Initializes to zero all local scalar variables of intrinsic
type INTEGER, REAL, COMPLEX, or LOGICAL that are saved but not
yet initialized. The default is -nozero. Use -save on the
command line to make all local variables specifically marked as
SAVE.
-Zp[n] Aligns fields of records and components of derived types on the
smaller of the size boundary specified or the boundary that
will naturally align them (same as the -align rec<n>byte
option). The [n] can be 1, 2, 4, 8, or 16. If you do not
specify [n], you get -Zp16, which is the default.
EXAMPLES
The following examples demonstrate optimization and multiple input
files:
1) ifort ax.f90
This command compiles ax.f90 producing executable file a.out.
Optimizations occur by default.
2) ifort -o abc ax.f90 bx.f90 cx.f90 -ipo
This command uses option -o to name the executable file abc and
compiles ax.f90, bx.f90, and cx.f90 as one program with interpro-
cedural analysis.
3) ifort -c ax.f90 bx.f90 cx.f90
This command uses option -c to suppress linking and produce indi-
vidual object files ax.o, bx.o, and cx.o. Interprocedural opti-
mizations are prevented.
4) ifort -c -O1 sub2.f90
ifort -c -O1 sub3.f90
ifort -o main.exe -g -O0 main.f90 sub2.o sub3.o
The first two commands show incremental compilation with minimal
optimization. The first command generates an object file for sub2;
the second generates an object file for sub3.
The last command uses option -O0 to disable all compiler default
optimizations. It uses option -g to generate symbolic debugging
information and line numbers in the object code, which can be used
by a source-level debugger.
RESTRICTIONS
The standard libraries, like libc, are loaded with the -l loader
option and not a full pathname. The wrong library can be loaded if
there are files with names like libc.a or libc.so in the directories
specified with the -L loader option, or in the default directories
searched by the loader.
For ifort, when multiple source files are compiled together without
the -c option, the suffix of the first source file determines the
default source form for the entire compilation.
DIAGNOSTICS
The ifort command produces diagnostic messages that are intended to be
self-explanatory. The loader can also produce occasional messages.
PREDEFINED SYMBOLS
The driver defines symbols (or macros) at the start of compilation and
when certain compiler options are specified during compilation.
The following symbols are defined on all systems at the start of com-
pilation:
__INTEL_COMPILER=910
__INTEL_COMPILER_BUILD_DATE=<YYYYMMDD>
__i386__ (i32 only)
__i386 (i32 only)
i386 (i32 only)
The following symbols are defined on Linux systems at the start of
compilation:
__ELF__
__linux__
__linux
linux
__gnu_linux__
__unix__
__unix
unix
__ia64__ (i64 only)
__ia64 (i64 only)
ia64 (i64 only; deprecated)
__x86_64__ (i32em only)
__x86_64 (i32em only)
The following symbols are defined on Mac OS systems at the start of
compilation:
__APPLE__
__MACH__
__PIC__
__pic__
The following symbols are defined on all systems during compilation if
certain compiler options are specified:
_OPENMP=200505
Defined if option -openmp is specified.
_PGO_INSTRUMENT
Defined if option -prof-gen is specified.
ENVIRONMENT VARIABLES
You can customize your environment by using run-time and compile-time
environment variables, or by using OpenMP or Profile Guided Optimiza-
tion (PGO) environment variables.
Run-Time Environment Variables
The following are run-time environment variables. For more informa-
tion on these variables, see the Intel(R) Fortran Building Applica-
tions guide.
Note that some environment variables are enabled (set to true) by
specifying Y, y, T, t, or 1; they are disabled (set to false) by spec-
ifying N, n, F, f, or 0.
decfort_dump_flag
If set to true, a core dump will be taken when any severe Intel
Fortran run-time error occurs. If the program is executing
under a debugger, a signal will be raised, which will allow you
to trace back to where the error was detected.
F_UFMTENDIAN
Lets you specify the numbers of the units to be used for lit-
tle-endian-big-endian conversion purposes.
FOR_ACCEPT
Lets you specify a file to be read from when the ACCEPT state-
ment is used.
FOR_DIAGNOSTIC_LOG_FILE
Lets you specify a file where diagnostic information should be
written.
FOR_DISABLE_DIAGNOSTIC_DISPLAY
If set to true, disables the display of all error information.
FOR_DISABLE_STACK_TRACE
If set to true, disables the call stack trace information that
follows the displayed severe error message text.
FOR_IGNORE_EXCEPTIONS
If set to true, disables the default run-time exception han-
dling.
FOR_NOERROR_DIALOGS
If set to true, disables the display of dialog boxes when cer-
tain exceptions or errors occur.
FOR_PRINT
Lets you specify a file to be written to when the PRINT state-
ment is used.
FOR_READ
Lets you specify a file to be read from when the READ statement
is used.
FOR_TYPE
Lets you specify a file to be written to when the TYPE state-
ment is used.
FORT_BUFFERED
If set to true, buffered I/O will be used at run time for out-
put of all Fortran I/O units, except those with output to the
terminal.
FORT_CONVERTn
Lets you specify the data format for an unformatted file asso-
ciated with a particular unit number (n).
FORT_CONVERT.ext and FORT_CONVERT_ext
Lets you specify the data format for unformatted files with a
particular file extension (ext).
FORTn Lets you specify the file name for a particular unit number
(n), when a file name is not specified in the OPEN statement or
an implicit OPEN is used, and option -fpscomp filesfromcmd is
not specified.
NLSPATH
Lets you specify the path for the Intel Fortran run-time error
message catalog.
TBK_ENABLE_VERBOSE_STACK_TRACE
If set to true, displays more detailed call stack trace infor-
mation in the event of an error.
TBK_FULL_SRC_FILE_SPEC
If set to true, displays complete file name information for
traceback output, including the path.
TEMP, TMP, and TMPDIR
Lets you specify an alternate working directory where temporary
files are created.
Compile-Time Environment Variables
The following are compile-time environment variables. For more infor-
mation on these variables, see the Intel(R) Fortran Building Applica-
tions guide.
FPATH The path for include files.
IFORTCFG
The configuration file to use instead of the default configura-
tion file.
LD_LIBRARY_PATH
The path for shared (.so) library files on Linux* systems.
DYLD_LIBRARY_PATH
The path for dynamic library files on Mac OS* systems.
PATH The path for compiler executable files.
TMPDIR The alternate working directory where scratch files are cre-
ated.
INTEL_LICENSE_FILE
The path to the product license file.
Standard OpenMP Environment Variables
The following are standard OpenMP environment variables. For more
information on these variables, see the Intel(R) Fortran Optimizing
Applications guide.
OMP_DYNAMIC
Enables (TRUE) or disables (FALSE) the dynamic adjustment of
the number of threads. The default value is FALSE.
OMP_NESTED
Enables (TRUE) or disables (FALSE) nested parallelism. The
default value is FALSE.
OMP_NUM_THREADS
Sets the number of threads to use during execution. The
default is the number of processors currently installed in the
system while generating the executable.
OMP_SCHEDULE
Specifies the type of run-time scheduling. The default is
static scheduling.
Intel(R) Extensions to OpenMP Environment Variables
The following are Intel extensions to the OpenMP environment vari-
ables. For more information on these variables, see the Intel(R) For-
tran Optimizing Applications guide.
KMP_LIBRARY
Selects the OpenMP run-time library throughput. The options for
the variable value are: serial, turnaround, or throughput indi-
cating the execution mode. The default value is throughput.
KMP_STACKSIZE
Sets the number of bytes to allocate for each parallel thread
to use as its private stack. Use the optional suffix b, k, m,
g, or t, to specify bytes, kilobytes, megabytes, gigabytes, or
terabytes. The default on IA-32 systems is 2m; the default on
Intel(R) EM64T and Itanium(R)-based systems is 4m.
Profile Guided Optimization Environment Variables
The following are Profile Guided Optimization (PGO) environment vari-
ables. For more information on these variables, see the Intel(R) For-
tran Optimizing Applications guide.
PROF_DIR
Specifies the directory in which dynamic information files are
created. This variable applies to all three phases of the pro-
filing process.
PROF_DUMP_INTERVAL
Initiates Interval Profile Dumping in an instrumented applica-
tion. Normally, the _PGOPTI_Set_Interval_Prof_Dump(int inter-
val) function activates Interval Profile Dumping and sets the
approximate frequency at which dumps will occur. The interval
parameter is measured in milliseconds and specifies the time
interval at which profile dumping will occur.
You can use this environment variable as an alternative method
of initiating Interval Profile Dumping. Set it to the desired
interval value before starting the application.
PROF_NO_CLOBBER
Alters the feedback compilation phase slightly. By default,
during the feedback compilation phase, the compiler merges the
data from all dynamic information files and creates a new
pgopti.dpi file if .dyn files are newer than an existing
pgopti.dpi file.
When this variable is set, the compiler does not overwrite the
existing pgopti.dpi file. Instead, the compiler issues a warn-
ing and you must remove the pgopti.dpi file if you want to use
additional dynamic information files.
TECHNICAL SUPPORT
The Intel Fortran Compiler product web site offers timely and compre-
hensive product information, including product features, white papers,
and technical articles. For the latest information, please visit
http://developer.intel.com/software/products/.
Intel also provides a support web site that contains a rich repository
of self-help information, including getting started tips, known prod-
uct issues, product errata, license information, user forums, and
more.
Registering your product entitles you to one year of technical support
and product updates through Intel(R) Premier Support. Intel Premier
Support is an interactive issue management and communication web site
that enables you to submit issues and review their status, and to
download product updates anytime of the day.
To register your product, to contact Intel, or to seek product sup-
port, please visit: http://www.intel.com/software/products/support.
SEE ALSO
icc(1), gprof(1), ld(1)
The Intel(R) Fortran Building Applications guide and the Intel Fortran
Optimizing Applications guide are the definitive sources for detailed
information on using the Intel Fortran Compiler.
In addition, see these other documents provided with the Intel Fortran
Compiler:
· Product Release Notes
· The Intel Fortran Compiler Options guide
· The Intel Fortran Language Reference
· The Intel Fortran Libraries Reference
You can access these documents from <install-direc-
tory>/doc/Doc_Index.htm. The default path is
/opt/intel/fc/9.x.xxx/doc/Doc_Index.htm (or .html).
COPYRIGHT INFORMATION
Copyright (C) 1985-2006, Intel Corporation.
* Other brands and names are the property of their respective owners.
------------------------------------------------------------------
Other annotations
------------------------------------------------------------------
dplace - a tool for controlling placement of processes onto cpus
-c Cpu_number(s) Specified as a list of cpu ranges:
Example: "-c1", "-c2-4", "-c1,4-8,3". Cpu numbers
are NOT physical cpu numbers. They are logical cpu
number that are relative to the cpus that are in
the set of allowed cpus as specified by the current
cpumemset or "runon" command. Cpu numbers start at
0. If this option is not specified, all cpus of the
current cpumemset are available.
taskset - retrieve or set a processes's CPU affinity (this tool
performs the same basic function as dplace, and for the
purposes of these benchmarks may be considered an alter-
native to dplace)
-c -c, --cpu-list
specifiy a numerical list of processors instead of
a bitmask. The list may contain multiple items,
separated by comma, and ranges. For example, 0,5,7,
9-11.
+FDO this is shorthand notation to indicate that feedback opti-
mization was used in the build. The actual compiler flag
used was -prof_gen for the first pass build, ie. before the
training run, and -prof_use for the second pass build
which is after the training run.
Extra Libraries: libsmartheap64.a
this denotes that the 64 bit version of MicroQuill SmartHeap
Library 7.01 or later, from www.microquill.com, was used.
The exact version used is documented under the Software
section of each submission.
------------------------------------------------------------------
Portability flags for SPEC CPU2000:
------------------------------------------------------------------
-Dalloca=__builtin_alloca Replace occurrences of alloca() with
__builtin_alloca.
-DSPEC_CPU2000_LP64 Compile using LP64 programming model.
-D_LIBC Don't nclude GNU C libraries
-DLINUX_i386 Linux Intel system, use "long long" as
64bit variable.
-DHAS_ERRLIST Prog env provides specification for
"sys_errlist[]".
-DSPEC_CPU2000_NEED_BOOL Use SPEC provided definition of the boolean type.
-DSPEC_CPU2000_LINUX_IA64 Compile for an IA64 system running Linux.
-DPSEC_CPU2000_GLIBC22 Compatibility with 2.2 & later versions of glibc
-DSYS_IS_USG Specifies that the operating system is
USG compliant.
-DSYS_HAS_TIME_PROTO Do not explicitly declare time().
-DSYS_HAS_SIGNAL_PROTO Do not explicitly #include <signal.h>
-DSYS_HAS_IOCTL_PROTO Do not explicitly declare ioctl().
-DSYS_HAS_ANSI System is ANSI compliant.
-DSYS_HAS_CALLOC_PROTO Do not explicitly declare calloc().
-FI Fixed-format F90 source code.