Fujitsu Siemens Computers SPEC CPU2006 Flag Description

The -fast option enhances execution speed across the entire program by including the following options that can improve run-time performance:

• -O3
• -no-prec-div
• -xT
• -ipo
• -static

To override one of the options set by /fast, specify that option after the -fast option on the command line. The exception is the -xT option which can't be overridden. The options set by /fast may change from release to release.

Enables O2 optimizations plus more aggressive optimizations, such as prefetching, scalar replacement, and loop and memory access transformations. Enables optimizations for maximum speed, such as:

• - Loop unrolling, including instruction scheduling
• - Code replication to eliminate branches
• - Padding the size of certain power-of-two arrays to allow more efficient cache use.

Enables optimizations for speed. This is the generally recommended optimization level. This option 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
  • - removal of unreferenced variables
• - The following capabilities for performance gain:
• - constant propagation
• - copy propagation
• - dead-code elimination
• - global register allocation
• - global instruction scheduling and control speculation
• - loop unrolling
• - optimized code selection
• - 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

Enables optimizations for speed and disables some optimizations that increase code size and affect speed.
To limit code size, this option:

• - Enables global optimization; this includes data-flow analysis, code motion, strength reduction and test replacement, split-lifetime analysis, and instruction scheduling.
• - Disables intrinsic recognition and intrinsics inlining.

Multi-file ip optimizations that includes:

• - inline function expansion
• - interprocedural constant propogation
• - dead code elimination
• - propagation of function characteristics
• - passing arguments in registers
• - loop-invariant code motion

Code is optimized for Intel(R) Core(TM)2 Duo processors, Intel(R) Core(TM)2 Quad processors and Intel(R) Xeon(R) processors with SSSE3. The resulting code may contain unconditional use of features that are not supported 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.

Do not use this option if you are executing a program on a processor that is not an Intel processor. If you use this option on a non-compatible processor to compile the main program (in Fortran) or the function main() in C/C++, the program will display a fatal run-time error if they are executed on unsupported processors.

-Qprec-dev improves precision of floating-point divides. It has a slight impact on speed. -Qprec-dev- disables this option and enables optimizations that give slightly less precise results than full IEEE division.

When you specify -Qprec-dev- along with some optimizations, such as -xN and -xB (Linux) or /QxN and /QxB (Windows), the compiler may change floating-point division computations into multiplication by the reciprocal of the denominator. For example, A/B is computed as A * (1/B) to improve the speed of the computation.

However, sometimes the value produced by this transformation is not as accurate as full IEEE division. When it is important to have fully precise IEEE division, do not use -Qprec-dev- which will enable the default -Qprec-dev and the result is more accurate, with some loss of performance.

-static prevents linking with shared libraries.

Instrument program for profiling for the first phase of two-phase profile guided otimization. This instrumentation gathers information about a program's execution paths and data values but does not gather information from hardware performance counters. The profile instrumentation also gathers data for optimizations which are unique to profile-feedback optimization.

Instructs the compiler to produce a profile-optimized executable and merges available dynamic information (.dyn) files into a pgopti.dpi file. If you perform multiple executions of the instrumented program, -prof-use merges the dynamic information files again and overwrites the previous pgopti.dpi file.
Without any other options, the current directory is searched for .dyn files.

Link with SmartHeap Library.
Available from: http://www.microquill.com

Enable/disable(DEFAULT) use of ANSI aliasing rules in optimizations; user asserts that the program adheres to these rules.

Tells the compiler the maximum number of times to unroll loops.

Enable/disable(DEFAULT) the compiler to generate prefetch instructions to prefetch data.

Specifies whether streaming stores are generated:

• always - enables generation of streaming stores under the assumption that the application is memory bound
• auto - compiler decides when streaming stores are used (DEFAULT)
• never - disables generation of streaming stores

/opt/intel/cc/10.0.023/bin/icc invokes the 32-bit Intel C compiler.
Also used to invoke linker for 32-bit C programs.

/opt/intel/cc/10.0.023/bin/icpc invokes the 32-bit Intel C++ compiler.
Also used to invoke linker for 32-bit C++ programs.

/opt/intel/cce/10.0.023/bin/icc invokes the 64-bit Intel C compiler.
Also used to invoke linker for 64-bit C programs.

/opt/intel/cce/9.1.049/bin/icc invokes the 64-bit Intel C compiler.
Also used to invoke linker for 64-bit C programs.

Invoke the Intel C compiler.
Also used to invoke linker for C programs.

Invoke the Intel C++ compiler.
Also used to invoke linker for C++ programs.

-I/opt/intel/cc/10.0.023/include is the include path of 32-bit Intel C/C++ compiler

-I/opt/intel/cce/10.0.023/include is the include path of 64-bit Intel C/C++ compiler

-I/opt/intel/cce/9.1.049/include is the include path of 64-bit Intel C/C++ compiler

-L/opt/intel/cc/10.0.023/lib is the library path of 32-bit Intel C/C++ compiler

-L/opt/intel/cce/10.0.023/lib is the library path of 64-bit Intel C/C++ compiler

-L/opt/intel/cce/9.1.049/lib is the library path of 64-bit Intel C/C++ compiler