Specifications

36 Performance-Centric Compiler Switches Chapter 3
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Compiler Usage Guidelines for AMD64 Platforms
3. Recompile the program with the -fb_opt fbdata switch.
Inter-Procedure Optimization. Use the -ipa switch to enable inter-procedure optimization.
-Ofast. For aggressive optimization, use the -Ofast switch. This is the shorthand for the switches
-O3, -OPT:Ofast, -ipa, and -fno-math-errno.
Linking with ACML.
The AMD Core Math Library (ACML) includes BLAS, LAPACK and FFT routines that are
optimized for AMD Athlon™ 64, AMD Opteron™ and AMD Family 10h processors. If the program
uses these routines, using ACML in place of generic C/Fortran implementation may greatly improve
the performance. For additional details on how to install this library and use it, see
http://developer.amd.com/assets/acml_userguide.pdf.
Refer to the PathScale EKOPath Compiler Suite User Guide, Version 2.1, for more options and
suggestions for tuning your application performance.
3.11 Intel Compilers (32-Bit) for Microsoft
®
Windows
®
The 32-bit Intel compilers can be installed and run on 32-bit Microsoft Windows on
AMD Athlon™ 64, AMD Opteron™ and AMD Family 10h processors.
3.11.1 Invocation Commands
The following commands invoke specific compilers:
• icl invokes the 32-bit Intel C/C++ compilers.
• ifort invokes the 32-bit Intel Fortran versions 9.1 and 10.0compilers.
3.11.2 Generic Performance Switches
Use of the -QxW -Qipo -O3 switches are recommended for Intel compiler version 10.0.
The -QxW switch instructs the compiler to optimize for Pentium 4 processor (including SSE2
instructions).
The -Qipo switch enables interprocedural (across multiple source files) analysis.
The -O3 optimizes for speed and includes several aggressive optimizations.
3.11.3 Other Switches
In addition to the switches mentioned in the program. It is worth experimenting with these switches.
Profile Guided Optimization. Intel compilers allow profile guided optimization. Use the following
steps for profile guided optimization with Intel compilers.
1. Compile the program with the -Qprof_gen switch. The -Qipo or -Qip switch is ignored by the
compiler if used with -Qprof_gen.