(ifort,) icc and icpc Compiler Options List
by
Tor Johansen
—
last modified
Aug 23, 2010 12:54 PM
Same info as displayed from 'icc -help' and 'icpc -help' on snykov.uit.no.
Intel(R) C/C++ Compiler / Itanium(R) Help
Usage:
icc [options] file1 [file2 ...] (C) ipcc [options] file1 [file2 ...] (C++)
where options represents zero or more compiler options. fileN is a C/C++ source (.C .c .cc .cpp .cxx .c++ .i .ii), assembly (.s .S), object (.o), static library (.a), or other linkable file. Commonly used options may be placed in the icc.cfg / icpc.cfg file.
Compiler Option List
Performance
| -O1 |
optimize for maximum compilation speed, but disable some optimizations which increase code size for a small speed benefit. Also disables software pipelining and global code scheduling |
| -O2 | enable optimizations (DEFAULT) |
| -O3 |
enable -O2 plus more aggressive optimizations that may not improve performance for all programs |
| -O0 | disable optimizations |
| -O | same as -O2 |
| -Os | enable speed optimizations, but disable some optimizations which increase code size for small speed benefit |
| -fast | enable -O3 -ipo -static |
| -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 -ip) |
| -falias | assume aliasing in program (DEFAULT) |
| -fno-alias | assume no aliasing in program |
| -ffnalias | assume aliasing within functions (DEFAULT) |
| -fno-fnalias |
assume no aliasing within functions, but assume aliasing across calls |
| -finline-functions | inline any function, at the compiler's discretion (same as -ip) |
| -fno-builtin |
disable inline expansion of intrinsic functions |
| -mp | maintain floating point precision (disables some optimizations) |
| -mp1 | improve floating-point precision (speed impact is less than -mp) |
| -m[no-]ieee-fp | same as -mp |
| -ffunction-sections | separate functions for the linker (COMDAT) |
| -f[no-]exceptions | enable(DEFAULT)/disable exception handling |
| -fdata-sections | same as -ffunction-sections |
| -mcpu=<cpu> |
optimize for a specific cpu itanium - optimize for Itanium(R) processor itanium2 - optimize for Itanium(R) 2 processor (DEFAULT) itanium2-p9000 - optimize for Dual-Core Intel(R) Itanium(R) 2 Processor 9000 Sequence |
| -mtune=<cpu> |
optimize for a specific cpu itanium - optimize for Itanium(R) processor itanium2 - optimize for Itanium(R) 2 processor (DEFAULT) itanium2-p9000 - optimize for Dual-Core Intel(R) Itanium(R) 2 Processor 9000 Sequence |
Advanced Performance
Enable and specify the scope of Interprocedural (IP) Optimizations:
| -ip | enable single-file IP optimizations (within files) |
| -ipo[n] | enable multi-file IP optimizations (between files) |
| -ipo-c | generate a multi-file object file (ipo_out.o) |
| -ipo-S | generate a multi-file assembly file (ipo_out.s) |
Modify the behavior of IP:
| -ip-no-inlining | disable IP inlining (requires -ip or -ipo) |
| -ipo-separate | create one object file for every source file (overrides -ipo[n]) |
Other Advanced Performance Options
| -unroll0 | disable loop unrolling |
| -unroll 0 | disable loop unrolling |
| -funroll-loops | unroll loops based on default heuristics |
| -prof-dir <d> | specify directory for profiling output files (*.dyn and *.dpi) |
| -prof-file <f> | specify file name for profiling summary file |
| -prof-gen[x] |
instrument program for profiling; with the x qualifier, extra information is gathered |
| -prof-use | enable use of profiling information during optimization |
| -prof-gen-sampling | prepare code for use with profrun sample gathering tool |
| -[no-]fnsplit | enable/disable function splitting (enabled with -prof-use) |
| -qp | compile and link for function profiling with UNIX gprof tool |
| -p | same as -qp |
| -[no-]prefetch | enable(DEFAULT)/disable prefetch insertion |
| -opt-report | generate an optimization report to stderr |
| -opt-report-file<file> | specify the filename for the generated report |
| -opt-report-level[level] | specify the level of report verbosity (min|med|max) |
| -opt-report-phase<name> | specify the phase that reports are generated against |
| -opt-report-routine<name> | reports on routines containing the given name |
| -opt-report-help | display the optimization phases available for reporting |
| -tcheck |
generate instrumentation to detect multi-threading bugs (requires Intel(R) Threading Tools; cannot be used with compiler alone) |
| -openmp |
enable the compiler to generate multi-threaded code based on the OpenMP directives |
| -openmp-profile |
link with instrumented OpenMP runtime library to generate OpenMP profiling information for use with the OpenMP component of the VTune(TM) Performance Analyzer |
| -openmp-stubs |
enables the user to compile OpenMP programs in sequential mode. The openmp directives are ignored and a stub OpenMP library is linked (sequential) |
| -openmp-report{0|1|2} | control the OpenMP parallelizer diagnostic level |
| -parallel |
enable the auto-parallelizer to generate multi-threaded code for loops that can be safely executed in parallel |
| -par-report{0|1|2|3} | control the auto-parallelizer diagnostic level |
| -par-threshold[n] |
set threshold for the auto-parallelization of loops where n is an integer from 0 to 100 |
| -[no-]alias-args |
enable(DEFAULT)/disable C/C++ rule that function arguments may be aliased; when disabling the rule, the user asserts that this is safe |
| -fargument-alias | same as -alias-args |
| -fargument-noalias | same as -no-alias-args |
| -fargument-noalias-global |
arguments do not alias each other and do not alias global storage |
| -[no-]ansi-alias |
enable/disable(DEFAULT) use of ANSI aliasing rules in optimizations; user asserts that the program adheres to these rules |
| -[no-]complex-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. |
| -ftls-model=<model> |
change thread-local storage model, where <model> can be the following: global-dynamic, local-dynamic, initial-exec or local-exec |
| -ivdep-parallel | make ivdep directives mean no loop carried dependencies |
| -mserialize-volatile |
enable strict memory access ordering for volatile data object references |
| -mno-serialize-volatile |
memory access ordering for volatile data object references may be suppressed |
| -[no-]ftz | enable/disable flush denormal results to zero |
| -[no-]IPF-fma |
enable/disable the combining of floating point multiplies and add/subtract operations |
| -[no-]IPF-fltacc |
enable/disable optimizations that affect floating point accuracy |
| -IPF-flt-eval-method0 |
floating point operands evaluated to the precision indicated by program |
| -IPF-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 |
| -[no-]IPF-fp-relaxed |
enable/disable use of faster but slightly less accurate code sequences for math functions |
| -auto-ilp32 |
specify that the application cannot exceed a 32-bit address space (-ipo[n] required) |
| -fp-model <name> |
enable <name> floating point model variation except[-] - enable/disable floating point semantics extended - enables intermediates in 80-bit precision fast - allows value-unsafe optimizations precise - allows value-safe optimizations source - enables intermediates in source precision strict - enables -fp-model precise -fp-model except and disables floating point multiply add |
Output, Debug, PCH
| -c | compile to object (.o) only, do not link |
| -S | compile to assembly (.s) only, do not link (*I) |
| -use-asm | produce objects through assembler |
| -fcode-asm |
produce assembly file with optional code annotations (requires -S) |
| -fsource-asm |
produce assembly file with optional source annotations (requires -S) |
| -f[no]verbose-asm |
produce assembly file with compiler comments (DEFAULT) (requires -S) |
| -o<file> | name output file |
| -g |
produce symbolic debug information in object file (implies -O0 when another optimization option is not explicitly set) |
| -g0 | disable generation of symbolic debug information |
| -debug [keyword] |
enable debug information and control output of enhanced debug information. keywords: all, full, minimal, none (same as -nodebug), inline-debug-info, variable-locations, semantic-stepping, extended, [no]expr-source-pos |
| -nodebug | do not enable debug information |
| -inline-debug-info |
preserve the source position of inlined code instead of assigning the call-site source position to inlined code |
| -ftrapuv | trap uninitialized variables |
| -pch | enable automatic precompiled header file creation/usage |
| -create-pch <file> | create precompiled header file |
| -use-pch <file> | use precompiled header file |
| -pch-dir <dir> | name precompiled header directory |
| -map-opts | enable option mapping tool |
| -print-multi-lib | print information about libraries being used |
C Preprocessor
| -A<name>[(val)] | create an assertion 'name' having value 'val' |
| -A- | remove all predefined macros |
| -C | don't strip comments |
| -D<name>[=<text>] | define macro |
| -E | preprocess to stdout |
| -EP | preprocess to stdout omitting #line directives |
| -P, -F | preprocess to file omitting #line directives |
| -I<dir> | add directory to include file search path |
| -idirafter<dir> | add directory to the second include file search path (after -I) |
| -isystem<dir> | add directory to the start of the system include path |
| -iprefix <prefix> | use <prefix> with -iwithprefix as a prefix |
| -iwithprefix <dir> |
append <dir> to the prefix passed in by -iprefix and put it on the include search path at the end of the include directories |
| -iwithprefixbefore <dir> |
similar to -iwithprefix except the include directory is placed in the same place as -I command line include directories |
| -U<name> | remove predefined macro |
| -imacros <file> |
treat <file> as an #include file, but throw away all preprocessing while macros defined remain defined |
| -X | remove standard directories from include file search path |
| -nostdinc | same as -X |
| -H | print include file order |
| -M | generate makefile dependency information |
| -MM | similar to -M, but do not include system header files |
| -MG | similar to -M, but treat missing header files as generated files |
| -MD |
preprocess and compile, generating output file containing dependency information ending with extension .d |
| -MMD | similar to -MD, but do not include system header files |
| -MF<file> |
generate makefile dependency information in file (must specify -M or -MM) |
| -MP |
add a phony target for each dependency |
| -MT<target> | change the default target rule for dependency generation |
| -MQ<target> | same as -MT, but quotes special Make characters |
| -dM | output macro definitions in effect after preprocessing (use with -E) |
| -no-gcc |
do not predefine the __GNUC__, __GNUC_MINOR__, and __GNUC_PATCHLEVEL__ macros |
Component Control
| -Qoption,<str>,<opts> | pass options <opts> to tool specified by <str> |
| -Qlocation,<str>,<dir> | set <dir> as the location of tool specified by <str> |
| -Qinstall <dir> |
set <dir> as root of compiler installation |
Language
| -[no]restrict | enable/disable the 'restrict' keyword for disambiguating pointers |
| -export | enable the export template feature |
| -export-dir <dir> | add directory to export template search path |
| -ansi | equivalent to GNU -ansi |
| -strict-ansi | strict ANSI conformance dialect |
| -[no-]c99 | enable/disable(DEFAULT) C99 support for C programs |
| -std=c99 | enable C99 support for C programs |
| -Kc++ | compile all source or unrecognized file types as C++ source files |
| -fno-rtti |
disable RTTI support |
| -Zp[n] | specify alignment constraint for structures (n=1,2,4,8,16) |
| -fshort-enums | allocate as many bytes as needed for enumerated types |
| -fsyntax-only | perform syntax and semantic checking only (no object file produced) |
| -funsigned-char | change default char type to unsigned |
| -funsigned-bitfields | change default bitfield type to unsigned |
| -fno-implicit-templates |
never emit code for non-inline templates which are instantiated implicitly; only emit code for explicit instantiations |
| -fno-implicit-inline-templates | do not emit code for implicit instantiations of inline templates |
| -ftemplate-depth-<n> | control the depth in which recursive templates are expanded |
| -fno-operator-names | disable support for operator name keywords |
| -fno-gnu-keywords | do not recognize 'typeof' as a keyword |
| -fpermissive | allow for non-conformant code |
Compiler Diagnostics
| -w | disable all warnings |
| -w<n> |
control diagnostics: n=0 display errors (same as -w) n=1 display warnings and errors (DEFAULT) n=2 display remarks, warnings, and errors |
| -wn<n> | print a maximum of n errors |
| -wd<L1>[,<L2>,...] | disable diagnostics L1 through LN |
| -we<L1>[,<L2>,...] | change severity of diagnostics L1 through LN to error |
| -ww<L1>[,<L2>,...] | change severity of diagnostics L1 through LN to warning |
| -wr<L1>[,<L2>,...] | change severity of diagnostics L1 through LN to remark |
| -Werror | force warnings to be reported as errors |
| -Wall | enable all warnings |
| -Wbrief | print brief one-line diagnostics |
| -Wcheck | enable more strict diagnostics |
| -W[no-]missing-prototypes | warn for missing prototypes |
| -W[no-]pointer-arith | warn for questionable pointer arithmetic |
| -W[no-]uninitialized | warn if a variable is used before being initialized |
| -Winline | enable inline diagnostics |
| -W[no-]deprecated | print warnings related to deprecated features |
| -W[no-]abi | warn if generated code is not C++ ABI compliant (DEFAULT) |
| -Wcontext-limit=<n> |
set maximum number of template instantiation contexts shown in diagnostic |
| -W[no-]unused-function | warn if declared function is not used |
| -W[no-]unknown-pragmas | warn if an unknown #pragma directive is used (DEFAULT) |
| -W[no-]main | warn if return type of main is not expected |
| -W[no-]comment[s] | warn when /* appears in the middle of a /* */ comment |
| -W[no-]return-type | warn when a function uses the default int return type and warn when a return statement is used in a void function |
| -Wp64 | print diagnostics for 64-bit porting |
| -[no]traceback |
specify whether the compiler generates data to allow for source file traceback information at runtime (only to be used when linking with Fortran programs) |
Miscellaneous
| -help | print this help message |
| -V | display compiler version information |
| --version | display GCC style version information |
| -dryrun | show driver tool commands but do not execute tools |
| -v | show driver tool commands and execute tools |
| -x <type> |
all source files found subsequent to -x <type> will be recognized as one of the following types: c - C source file c++ - C++ source file c-header - C header file cpp-output - C pre-processed file c++-cpp-output - C++ pre-processed file assembler - assembly file assembler-with-cpp - assembly file that needs to be preprocessed none - disable recognition, and revert to file extension |
| -[no-]sox |
enable/disable(DEFAULT) saving of compiler options and version in the executable |
| -fr32 | disable use of high floating point registers |
| -kernel |
generate code for inclusion in the kernel. Prevents generation of speculation as support may not be available when code runs. Suppresses software pipelining |
| -reserve-kernel-regs |
reserves certain registers (f12-f15, f32-f127) for use by the kernel. These will not be used by the compiler |
| -mfixed-range=f12-f15,f32-f127 |
reserves certain registers (f12-f15, f32-f127) for use by the kernel |
| -f[no-]pic, -f[no-]PIC |
required to build fully preemptable and position independent code for shared objects (OFF by default) |
| -fvisibility=[extern|default| protected|hidden| internal] |
Global symbols (data and functions) will get the visibility attribute given by default. Symbol visibility attributes explicitly set in the source code or using the symbol visibility attribute file options will override the -fvisibility setting |
| -fvisibility-extern=<file> |
Space separated symbols listed in the <file> argument will get visibility set to extern |
| -fvisibility-default=<file> |
Space separated symbols listed in the <file> argument will get visibility set to default |
| -fvisibility-protected=<file> |
Space separated symbols listed in the <file> argument will get visibility set to protected |
| -fvisibility-hidden=<file> |
Space separated symbols listed in the <file> argument will get visibility set to hidden |
| -fvisibility-internal=<file> |
Space separated symbols listed in the <file> argument will get visibility set to internal |
| -fminshared |
Compilation is for the main executable. Absolute addressing can be used and non-position independent code generated for symbols that are at least protected |
| -f[no-]common |
Enables the compiler to treat common variables as if they were defined. That in turn allows the use of gprel addressing of common data variables |
| -fpack-struct | pack structure members together |
| -freg-struct-return | return struct and union values in registers when possible |
| -fno-builtin-<func> | disable the <func> intrinsic |
| -f[no-]math-errno | set ERRNO after calling standard math library functions |
| -nobss-init |
disable placement of zero-initialized variables in BSS (use DATA) |
| -[no-]global-hoist | enable(DEFAULT)/disable external globals are load safe |
| -gcc-name=<name> | name and location of gcc if not where expected |
| -gcc-version=<version> |
specify the <version> of gcc compatibility. Default value matches gcc version installed 320 - gcc 3.2 compatibility 330 - gcc 3.3 compatibility 340 - gcc 3.4 compatibility 400 - gcc 4.0 compatibility |
| -B<prefix> | find libraries, headers and executables in <prefix> |
| -[no-]multibyte-chars | provide support for multi-byte characters |
| -fabi-version=<val> |
directs the compiler to select a specific ABI implementation 0 - most recent ABI implementation 1 - g++ 3.2 compatible ABI implementation 2 - most conformant ABI implementation |
Linking/Linker
| -L<dir> | instruct linker to search <dir> for libraries |
| -i-dynamic | link Intel provided libraries dynamically |
| -i-static | link Intel provided libraries statically |
| -mrelax | pass -relax to the linker (DEFAULT) |
| -mno-relax | do not pass -relax to the linker |
| -dynamic-linker<file> | select dynamic linker other than the default |
| -no-cpprt | do not link in C++ runtime libraries |
| -nodefaultlibs | do not use standard libraries when linking |
| -nostartfiles | do not use standard startup files when linking |
| -nostdlib | do not use standard libraries and startup files when linking |
| -static | prevents linking with shared libraries |
| -shared | produce a shared object |
| -static-libcxa | link Intel libcxa C++ library statically |
| -shared-libcxa |
link Intel libcxa C++ library dynamically, overrides the default behavior when -static is used |
| -cxxlib-<mode> |
tell the compiler which C++ run-time libraries to use gcc[=dir] - link using C++ run-time libraries provided with gcc (default on systems running gcc 3.2 or above) dir is an optional top-level location for the gcc binaries and libraries icc - link using C++ run-time libraries provided by Intel (default on systems running a gcc version lower than 3.2) |
| -u <symbol> | pretend the <symbol> is undefined |
| -T <file> | direct linker to read link commands from <file> |
| -Xlinker <val> | pass <val> directly to the linker for processing |
| -Wa,<o1>[,<o2>,...] | pass options o1, o2, etc. to the assembler |
| -Wl,<o1>[,<o2>,...] | pass options o1, o2, etc. to the linker for processing |
| -Wp,<o1>[,<o2>,...] | pass options o1, o2, etc. to the preprocessor |
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