Description of compiler flags for Intel C++ Compiler 9.1 -------------------------------------------------------- -O1 optimize for speed, but disable some optimizations which increase code size for a small speed benefit. Includes inline expansion except for intrinsic functions, global optimizations, string pooling optimizations. -O2 This is the default level of optimization. Optimizes for speed. The -O2 option includes O1 optimizations and in addition enables inlining of intrinsics and more speed optimizations. -O3 Builds on -01 and -02 optimizations by enabling high-level optimization. This level does not guarantee higher performance unless loop and memory access transformation take place. In conjunction with -QaxK/-QxK and QaxW/QxW, this switch causes the compiler to perform more aggressive data dependency analysis than for -O2. This may result in longer compilation times. -Oa[-] assume [do not assume] no aliasing in program -Qax generate code specialized for processors specified by while also generating generic IA-32 code. includes one or more of the following characters: K Intel Pentium III and compatible Intel processors W Intel Pentium 4 and compatible Intel processors N Intel Pentium 4 and compatible Intel processors. Enables new optimizations in addition to Intel processor-specific optimizations P Intel Pentium 4 processors and compatible Intel processors with Streaming SIMD Extensions 3 B Intel Pentium M and compatible Intel processors -Qx (Windows) -x (Linux) Generate specialized code for processor specified by while also generating generic code. is the processor for which you want to target your program. Possible values are: K: Code is optimized for Intel® Pentium® III and compatible Intel processors. W: Code is optimized for Intel Pentium 4 and compatible Intel processors. N: Code is optimized for Intel Pentium 4 and compatible Intel processors with Streaming SIMD Extensions 2. 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. B: Code is optimized for Intel Pentium M and compatible Intel processors. This option also enables new optimizations in addition to Intel processor-specific optimizations. P: Code is optimized for Intel® Core™ Duo processors, Intel® Core™ Solo processors, Intel® Pentium® 4 processors with Streaming SIMD Extensions 3, and compatible Intel processors with Streaming SIMD Extensions 3. 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. Additional Notes on N and P: ------------------------------------ The N and P options target your program to run on Intel Pentium 4 and compatible Intel processors. The resulting code might contain unconditional use of features that are not supported on other processors. Programs, where the function main() is compiled with this option, will detect non compatible processors and generate an error message during execution. These options also enable new optimizations in addition to Intel processor-specific optimizations including advanced data layout and code restructuring optimizations to improve memory accesses for Intel processors. /arch:{SSE|SSE2} same as -QxK and -QxW respectively -Ob{0|1|2} Controls the compiler's inline expansion. 0: disable inlining. 1 inline functions declared with __inline, and perform C++ inlining 2 inline any function, at the compiler's discretion (same as -Qip) -Qip enable single-file IP optimizations (within files, same as -Ob2) -Qipo 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 -fast The -fast option enhances execution speed across the entire program by including the following options that can improve run-time performance: -O3 (maximum speed and high-level optimizations) -Qipo (enables interprocedural optimizations across files) -QxP (generate code specialized for Intel Pentium 4 processor and compatible Intel processors with Streaming SIMD Extensions 3) -Qprec-div- (disable -Qprec-div) where -Qprec-div improves precision of FP divides (some speed impact) To override one of the options set by /fast, specify that option after the -fast option on the command line. The options set by /fast may change from release to release. -Qansi_alias[-] enable/disable use of ANSI aliasing rules in optimizations; user asserts that the program adheres to these rules. The default for C++ is -Qansi_alias- which is that aliasing rules are not assumed. The default for the Fortran compiler is -Qansi_alias as described in the next section. For C++, the -Qansi_alias flag will enable optimizations that would otherwise be prevented by potential aliasing. -Qprof_gen instrument program for profiling for the first phase of two-phase profile guided otimization -Qprof_use 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, -Qprof_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 -Qrcd The Intel compiler uses the -Qrcd 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. This means that values are rounded during floating point calculations. 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 -Qrcd option disables the change to truncation of the rounding mode for all floating point calculations, including floating point-to-integer conversions. Turning on this option can improve performance, but floating point conversions to integer will not conform to C semantics. -Qunroll[n] Specifies the maximum number of times to unroll a loop. Omit n to let the compiler decide whether to perform unrolling or not. Use n = 0 to disable unroller. If n is not specified, the compiler automatically chooses the maximum number of times to unroll a loop. -Qcxx_features Enables both -GX and -GR as described below so C++ Runtime Type Information and Exception Handling are both enabled -GX Enables the full C++ Exception Handling unwind semantics. -GR Enables C++ Runtime Type Information (RTTI). -Zp{1|2|4|8|16} Specifies the strictest alignment constraint for structure and union types as one of the following: 1, 2, 4, 8, or 16 (default) bytes. -Qprefetch[-] Enables [disables] the insertion of software prefetching by the compiler. Default is -Qprefetch. +FDO PASS1=-Qprof_gen PASS2=-Qprof_use Using feedback-directed optimization, a profile is generated on the first pass of compilation and used on the second pass. shlW32M.lib: MicroQuill SmartHeap Library 8.0 available from http://www.microquill.com/ Description of compiler flags for Intel FORTRAN Compiler 9.1 ------------------------------------------------------------- -O1 optimize for speed, but disable some optimizations which increase code size for a small speed benefit. Includes inline expansion except for intrinsic functions, global optimizations, string pooling optimizations. -O2 This is the default level of optimization. Optimizes for speed. The -O2 option includes O1 optimizations and in addition enables inlining of intrinsics and more speed optimizations. -O3: Builds on -01 and -02 optimizations by enabling high-level optimization. This level does not guarantee higher performance unless loop and memory access transformation take place. In conjunction with -QaxK/-QxK and QaxW/QxW, this switch causes the compiler to perform more aggressive data dependency analysis than for -O2. This may result in longer compilation times. -Qax generate code specialized for processors specified by while also generating generic IA-32 code. includes one or more of the following characters: K Intel Pentium III and compatible Intel processors W Intel Pentium 4 and compatible Intel processors N Intel Pentium 4 and compatible Intel processors. Enables new optimizations in addition to Intel processor-specific optimizations P Intel Pentium 4 processors and compatible Intel processors with Streaming SIMD Extensions 3 B Intel Pentium M and compatible Intel processors -Qx (Windows) -x (Linux) Generate specialized code for processor specified by while also generating generic code. is the processor for which you want to target your program. Possible values are: K: Code is optimized for Intel® Pentium® III and compatible Intel processors. W: Code is optimized for Intel Pentium 4 and compatible Intel processors. N: Code is optimized for Intel Pentium 4 and compatible Intel processors with Streaming SIMD Extensions 2. 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. B: Code is optimized for Intel Pentium M and compatible Intel processors. This option also enables new optimizations in addition to Intel processor-specific optimizations. P: Code is optimized for Intel® Core™ Duo processors, Intel® Core™ Solo processors, Intel® Pentium® 4 processors with Streaming SIMD Extensions 3, and compatible Intel processors with Streaming SIMD Extensions 3. 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. Additional Notes on N and P: ------------------------------------ The N and P options target your program to run on Intel Pentium 4 and compatible Intel processors. The resulting code might contain unconditional use of features that are not supported on other processors. Programs, where the function main() is compiled with this option, will detect non compatible processors and generate an error message during execution. These options also enable new optimizations in addition to Intel processor-specific optimizations including advanced data layout and code restructuring optimizations to improve memory accesses for Intel processors. /arch:{SSE|SSE2} same as -QxK and -QxW respectively -Qip enable single-file IP optimizations (within files, same as -Ob2) -Qipo 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 -fast The -fast option enhances execution speed across the entire program by including the following options that can improve run-time performance: -O3 (maximum speed and high-level optimizations) -Qipo (enables interprocedural optimizations across files) -QxP (generate code specialized for Intel Pentium 4 processor and compatible Intel processors with Streaming SIMD Extensions 3) -Qprec-div- (disable -Qprec-div) where -Qprec-div improves precision of FP divides (some speed impact) To override one of the options set by -fast, specify that option after the -fast option on the command line. The options set by -fast may change from release to release. -Qansi_alias Enables (default) or disables the compiler to assume that the program adheres to the ANSI Fortran type aliasability rules. For example, an object of type real cannot be accessed as an integer. You should see the ANSI standard for the complete set of rules. The default for this flag is the reverse in C++, as noted in the previous section. -Qprof_gen instrument program for profiling for the first phase of two-phase profile guided otimization -Qprof_use 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, -Qprof_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 -Qrcd Enables fast float-to-int conversion. -Qscalar_rep(-) Enables(disables) scalar replacement performed during loop transformations (requires /O3). Such replacement is disabled by default. -Qauto Causes all variables to be allocated on the stack, rather than in local static storage. Does not affect variables that appear in an EQUIVALENCE or SAVE statement, or those that are in COMMON. Makes all local variables AUTOMATIC, same as /4Ya. -Qunroll[n] Specifies the maximum number of times to unroll a loop. Omit n to let the compiler decide whether to perform unrolling or not. Use n = 0 to disable unroller. If n is not specified, the compiler automatically chooses the maximum number of times to unroll a loop. -Qprefetch[-] Enables [disables] the insertion of software prefetching by the compiler. Default is -Qprefetch. Other Notes: ------------ "/" and "-" are both allowable starting tokens for flags passed to the compiler i.e. -QxK and /QxK are identical switches. Portability options for CPU2000: ------------------------------- 176.gcc: -Dalloca=_alloca : so as to 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. -F32000000 : Same as with 176.gcc, pre-allocates a 32MB stack 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: -DHAS_ERRLIST : Prog env provides specification for "sys_errlist[]". 253.perlbmk: -DSPEC_CPU2000_NTOS : This ensures some of the code changes necessary for compilation on Windows, get included -DPERLDLL : For Windows, SPEC modified the original perl source code to allow building a monolithic executable rather than the executable and DLL that is standard on Windows. -DPERLDLL is simply a signal to the Perl source code that it is being built as if it were to go into the DLL. The SPEC version of perl, in 253.perlbmk, will not build on Windows without this flag. /MT : Use the static multi-threaded library else it will not compile. 254.gap: -DSYS_HAS_CALLOC_PROTO : -DSYS_HAS_MALLOC_PROTO : These two pre-defines tell of the existence of malloc and calloc prototypes.