Hacker Newsnew | past | comments | ask | show | jobs | submitlogin

    gcc 4.8.0: 1.640625 +/- 3.703323
    clang 3.2: 1.718750 +/- 3.772718
    chrome   : 23.28515625 +/- 3.636932727324763
So chrome is about ~14x the native compilers.

Changing gcc to use -O2 instead of -O3 gets: 1.562500 +/- 3.630922.



What about -Ofast which enables -ffast-math?


The makefile supplied with the repo specifies -ffast-math. It uses these CFLAGS:

    CFLAGS=-s -O3 -msse -mfpmath=sse -ffast-math -fomit-frame-pointer -IBox2D_v2.2.1 -DNDEBUG=1
Using -Ofast gets the same results as -O2.


Thanks for the info, I should have guessed that he enabled -ffast-math manually.




Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: