IBM AIX Flag Disclosure
SPEC CPU2000
Last Revised 24 October, 2001
Source Level Portability Options
================================
-DHOST_WORDS_BIG_ENDIAN (176.gcc)
Host system is big-endian.
-DAIX (186.crafty)
Sets some basic parameters like endian-ess, OS type, and ANSI
language extensions to be compatible with an AIX system.
-DNEED_EXPLICIT_SPECIALIZATION (252.eon)
Supply function definitions with explicit types in two cases
where templatized versions fail to compile.
-DSPEC_CPU2000_AIX (253.perlbmk)
Compile the SPEC CPU2000 modified perl for an AIX system.
-DSYS_IS_BSD (254.gap)
Compile gap for a BSDish system.
-DSYS_STRING_H (254.gap)
Do not explicitly include string.h
-DSYS_HAS_TIME_PROTO (254.gap)
Do not supply prototypes for the time(), times() and getrusage()
functions.
-DSYS_HAS_MALLOC_PROTO (254.gap)
Do not supply prototypes for malloc() and free().
-DSYS_HAS_CALLOC_PROTO (254.gap)
Do not supply a prototype for calloc().
-DHAVE_SIGNED_CHAR (300.twolf)
System allows signed char type.
Compiler Invocation
===================
xlc Invokes the compiler for C source files with a default language level
of ansi and specifies that it allow type-based aliasing.
cc Invokes the compiler for C source files with a default language of
extended and specifies that it provide compatibility with older IBM
compilers and allow placement of string literals or constant values in
read/write storage. cc does not conform to the ISO/ANSI C standard.
Compiler Options
================
-ma Use built-in alloca() function.
-O Performs optimizations that the compiler developers considered
the best combination for compilation speed and runtime
performance.
-O3 Perform some memory and compile time intensive optimizations in
addition to those executed with -O. The -O3 specific
optimizations have the potential to slightly alter the semantics
of a user's program. Optimizations may include, but are not
limited to: Aggressive code motion, and scheduling on
computations that have the potential to raise an exception;
Relaxed conformance to IEEE rules in cases where the difference
in the results is not important to an application; Rewriting of
floating point expressions.
-O4 Equivalent to -O3 -qipa -qhot with automatic generation of
architecture ( -qarch= )and tuning ( -qtune= )options ideal for
that platform. The qipa level defaults to level=1.
-O5 Equivalent to -O3 -qipa=level=2 -qhot with automatic generation
of architecture ( -qarch= ) and tuning ( -qtune= ) options ideal
for that platform.
-Q, -qinline The -Q option without any list inlines all appropriate
procedures, subject to limits on the number of inlined calls and
the amount of code size increase as a result. -qinline is an
alias for -Q.
-Q=xxx Inline all functions that contain less than xxx lines of
abstract code units.
-q64 Selects 64-bit compiler mode.
-qalign=natural The compiler maps structure members to their natural
boundaries.
-qansialias Use type-based aliasing during optimization
-qarch=ppc Produces object code containing instructions that will run on
any of the 32-bit PowerPC hardware platforms.
-qarch=pwr3 Produces object code containing instructions that will run on
power3 processors.
-qarch=rs64b Produces object code containing instructions that will run on
RS64-II processors.
-qessl=yes Specifies that, if either -lessl or -lesslsmp are also
specified, then Engineering and Scientific Subroutine Library
(ESSL) routines should be used in place of some Fortran 90
intrinsic procedures when there is a safe opportunity to do so.
-qfixed Indicates that the input source program is in fixed form. Allows
fixed format Fortran 77 programs to be compiled using the xlf90
compiler invocation.
-qhot perform high-order transformations on loops during optimization.
-qipa=level=1 Turns on interprocedural analysis with inlining, limited alias
analysis, and limited call-site tailoring. This is the default
level of -qipa.
-qipa=level=2 Turns on interprocedural analysis with inlining, cloning, full
alias analysis, constant propagation, call-site tailoring, and
dead code removal.
-qinline Alias for -Q. See -Q.
-qipa=partition=large Specifies the size of the regions within the program to
analyze. Larger partitions contain more procesures,
which result in better interprocedural analysis but
require more storage to optimize.
-qlanglvl=ansi Compilation conforms to the ANSI standard.
-qpdf/pdf2 Profile directed feedback optimization
-qsuffix=f=f90 Sets the suffix for source files to be .f90. The .f90 suffix is
required by xlf90 to compile Fortran 90 programs.
-qtune=604 Instruction selection, scheduling, and other implementation
dependent performance enhancements for the PowerPC 604/604e processor.
-qtune=pwr3 Instruction selection, scheduling, and other implementation
dependent performance enhancements for the Power3 processor.
-qtune=rs64b Instruction selection, scheduling, and other implementation
dependent performance enhancements for the RS64-II processor.
Linker Options
==============
-lessl Link the Engineering and Scientifc Subroutine Library (ESSL).
-lmass Link the mathematical acceleration subsystem libraries (MASS),
which contain libraries of tuned mathematical intrinsic
functions. See www.austin.ibm.com/tech/MASS.
-lhmu Link fast malloc libraries. These libraries are part of the
memdbg package that is included with IBM C compilers.
-lpdf Routines used in the first pass of the profile directed
feedback process. Routines from this library are not used in
building the final executable.
-bnso Brings referenced library procedures into the object file
-bI:/lib/syscalls.exp Create statically linked object files (syscalls.exp
supplies the names of the routines that can be
imported).
FDPR:
-----
The fdpr (feedback directed program restructuring) program optimizes the
executable image of a program by collecting information on the behavior of
the program while the program is used for some typical workload, and then
creating a new version. It is available on AIX Version 4 systems as part
of the Performance Toolbox for AIX.
Options:
-p ProgramName The name of the executable program to optimize.
-v Selects verbose output during processing/compilation
-x Command Specifies the command used for invoking the instrumented
program. All the arguments after the -x flag are used
for the invocation.
-R2 Employ a program-reordering technique in which the
original structure of the program, including traceback
entries, is preserved.
-R3 Employ global reordering techniques that do not preserve
debug information.