Intel(R) 8.1 C++ Compiler / Itanium(R) option list
----------------------------------------------------
Performance
-----------
/O1 optimize for maximum speed, but disable some optimizations which
increase code size for a small speed benefit. Also disables software
pipelining and global code scheduling: /Gfsy /Ob1gysi- /Qunroll0
/O2 optimize for maximum speed (DEFAULT): /Gfsy /Ob1gyti
/O3 optimize for maximum speed and enable high-level optimizations
/Ox enable maximum optimizations: /Gs /Ob1gyti (same as /O2 without /Gfy)
/Od disable optimizations; useful for selective optimizations (i.e. /Od /Og)
/fast enable /O3 /Qipo
/Ob<n> control inline expansion:
n=0 disables inlining
n=1 inline functions declared with __inline, and perform C++ inlining
n=2 inline any function, at the compiler's discretion (same as /Qip)
/Og enable global optimizations
/Oi[-] enable/disable inline expansion of intrinsic functions
/Op[-] enable/disable better floating-point precision
/Os enable speed optimizations, but disable some optimizations which
increase code size for small speed benefit (overrides /Ot)
/Ot enable speed optimizations (overrides /Os)
/Oa[-] assume no aliasing in program
/Ow[-] assume no aliasing within functions, but assume aliasing across calls
/G1 optimize for Itanium(R) processor
/G2 optimize for Itanium(R) 2 processor (DEFAULT)
/GR[-] enable/disable C++ RTTI
/GX[-] enable/disable C++ exception handling (/GX is same as /EHsc)
/Qcxx_features
enable standard C++ features (-GX -GR)
/EHa enable asynchronous C++ exception handling model
/EHs enable synchronous C++ exception handling model
/EHc assume extern "C" functions do not throw exceptions
/Ge enable stack checks for all functions
/Gs[n] disable stack checks for functions with less than n bytes of locals
/Gf enable string pooling optimization
/GF enable read-only string pooling optimization
/Gy separate functions for the linker (COMDAT)
/GA optimize for Windows application (assume .exe)
/GT enable fiber-safe thread local storage
/Qnopic disable generation of position independent code
/Ap64 assume 64-bit size for pointers (DEFAULT)
/As32 assume 32-bit address space
/As64 assume 64-bit address space (DEFAULT)
Advanced Performance
--------------------
Enable and specify the scope of Interprocedural (IP) Optimizations:
/Qip enable single-file IP optimizations (within files, same as /Ob2)
/Qipo[n] enable multi-file IP optimizations (between files)
/Qipo_c generate a multi-file object file (ipo_out.obj)
/Qipo_S generate a multi-file assembly file (ipo_out.asm)
Modify the behavior of IP:
/Qip_no_inlining disable IP inlining (requires /Qip or /Qipo)
/Qipo_obj force generation of real object files (requires /Qipo)
/Qipo_separate create one object file for every source file
(overrides /Qipo[n])
Other Advanced Performance Options:
/Qunroll0 disable loop unrolling
/Qprof_dir <d> specify directory for profiling output files (*.dyn and *.dpi)
/Qprof_file <f> specify file name for profiling summary file
/Qprof_gen[x] instrument program for profiling; with the x qualifier, extra
information is gathered for use with the PROFORDER tool
/Qprof_use enable use of profiling information during optimization
/Qfnsplit[-] enable/disable function splitting (enabled with /Qprof_use)
/Qopt_report generate an optimization report to stderr
/Qopt_report_file<file> specify the filename for the generated report
/Qopt_report_level[level] specify the level of report verbosity (min|med|max)
/Qopt_report_phase<name> specify the phase that reports are generated against
/Qopt_report_routine<name> reports on routines containing the given name
/Qopt_report_help display the optimization phases available for
reporting
/Qtcheck generate instrumentation to detect multi-threading bugs
(requires Intel(R) Threading Tools; cannot be used with
compiler alone)
/Qopenmp enable the compiler to generate multi-threaded code
based on the OpenMP directives
/Qopenmp_profile link with instrumented OpenMP runtime library to
generate OpenMP profiling information for use with the
OpenMP component of the VTune(TM) Performance Analyzer
/Qopenmp_stubs enables the user to compile OpenMP programs in
sequential mode. The openmp directives are ignored and
a stub OpenMP library is linked (sequential)
/Qopenmp_report{0|1|2} control the OpenMP parallelizer diagnostic level
/Qparallel enable the auto-parallelizer to generate multi-threaded
code for loops that can be safely executed in parallel
/Qpar_report{0|1|2|3} control the auto-parallelizer diagnostic level
/Qpar_threshold[n] set threshold for the auto-parallelization of loops
where n is an integer from 0 to 100
/Qalias_args[-] enable(DEFAULT)/disable C/C++ rule that function
arguments may be aliased; when disabling the rule, the
user asserts that this is safe
/Qansi_alias[-] enable/disable(DEFAULT) use of ANSI aliasing rules in
optimizations; user asserts that the program adheres to
these rules
/Qcomplex_limited_range[-] enable/disable(DEFAULT) the use of the basic
algebraic expansions of some complex arithmetic
operations. This can allow for some performance
improvement in programs which use a lot of complex
arithmetic at the loss of some exponent range.
/Qchkstk[-] enable/disable call _chkstk for every call to alloca()
/Qivdep_parallel make ivdep directives mean no loop carried dependencies
/Qserialize-volatile[-]
enable/disable strict memory access ordering for
volatile data object references
/Qftz[-] enable/disable flush denormal results to zero
/QIPF_fma[-] enable/disable the combining of floating point
multiplies and add/subtract operations
/QIPF_fltacc[-] enable/disable optimizations that affect floating
point accuracy
/QIPF_flt_eval_method0 floating point operands evaluated to the precision
indicated by program
/QIPF_fp_speculation<mode> enable floation point speculations with the
following <mode> conditions:
fast - speculate floating point operations (DEFAULT)
safe - speculate only when safe
strict - same as off
off - disables speculation of floating-point operations
/QIPF_fp_relaxed[-] enable/disable use of faster but slightly less accurate
code sequences for math functions
/Qauto_ilp32 specify that the application cannot exceed a 32-bit
address space (/Qipo[n] required)
Portability options for CPU2000:
-------------------------------
175.vpr:
--------
-DSPEC_CPU2000_P64: Necessary to enable the P64 porting changes
176.gcc:
--------
-Dalloca=_alloca : Use the built-in optimized alloca
/Fn : 176.gcc uses alloca and this options tells
the linker to pre-allocate n bytes of stack.
The default amount of stack allocated is not
enough and 176.gcc crashes with a run-time
error
178.galgel:
-----------
-FI : Fixed-format F90 source code.
181.mcf:
--------
-DSPEC_CPU2000_P64: Necessary to enable the P64 porting changes
186.crafty:
-----------
-DNT_i386 : Specifies that it is a Windows NT Intel
processor-based system which makes the compiler
use "long long" as the 64-bit variable that
186.crafty needs.
252.eon:
--------
-DSPEC_CPU2000_P64: Necessary to enable the P64 porting changes
253.perlbmk:
------------
-DSPEC_CPU2000_NTOS: This enables the code changes for porting to
Windows get included
-DPERLDLL : On Windows, we need a perl.exe instead of a
perl.exe and perl.dll. This pre-define ensures
that the changes necessary to get a single,
UNIX-style executible without getting the
indirect calls that can cause a 10% performance
degradation. This allows the Windows-based
executible to be as close as possible to
the Unix-based one.
-DSPEC_CPU2000_P64: Necessary to enable the P64 porting changes
-DHAS_LONG_LONG
-DUSE_LONG_LONG : Make the compiler use "long long" as the 64-bit integer variables
254.gap:
--------
-DSPEC_CPU2000 :
-DSPEC_CPU2000_P64: Necessary to enable the P64 porting changes
255.vortex:
-----------
-DSPEC_CPU2000_P64: Necessary to enable the P64 porting
-D_WIN32 : To include <windows.h> function prototypes