最終更新:2019-09-18 (水) 17:41:03 (1679d)
GCC/最適化
https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html
gcc -O
gcc -Os
- Optimize for size.
gcc -Ofast?
- Disregard strict standards compliance.
- enables all -O3 optimizations. It also enables optimizations that are not valid for all standard-compliant programs. It turns on -ffast-math and the Fortran-specific -fno-protect-parens? and -fstack-arrays?.
gcc -Og?
- Optimize debugging experience.
- enables optimizations that do not interfere with debugging.
gcc -O3
- Optimize yet more.
- turns on all optimizations specified by -O2 and also turns on the -finline-functions?, -funswitch-loops?, -fpredictive-commoning?, -fgcse-after-reload?, -ftree-loop-vectorize?, -ftree-loop-distribute-patterns?, -ftree-slp-vectorize?, -fvect-cost-model?, -ftree-partial-pre? and -fipa-cp-clone? options.
gcc -O2
- Optimize even more.
- デバッグを考慮せず最適化オプションを指定
- GCC performs nearly all supported optimizations that do not involve a space-speed tradeoff. As compared to -O, this option increases both compilation time and the performance of the generated code.
gcc -O1?/gcc -O
- Optimize.
- デバッグに支障のないものだけが有効化
- Optimizing compilation takes somewhat more time, and a lot more memory for a large function.
gcc -O0?
- 何も指定しない場合、これがデフォルト
- Reduce compilation time and make debugging produce the expected results.
表示
- gcc -O1 -Q --help=optimize
参考
https://cpplover.blogspot.jp/2013/07/gcc.html関連
- gcc -march=native
