902317 - Make builders use -fp:fast safely on MSVC2010+

Status: RESOLVED WONTFIX

(Firefox Build System :: General, defect)

Description

[xunxun]

Attachment: Make builders use -fp:fast safely on MSVC2010+

MSVC -fp:fast can improve firefox's some performance, and can make some VC functions intrinsic, but some modules can not be built using -fp:fast because of problems.

The patch can make the modules avoid to use -fp:fast.

I only test the patch on MSVC2010.

Because MSVC2005's -fp:fast is much more aggressive than MSVC2010, I suggest not to use -fp:fast on MSVC2005.

Comment 1

[Mike Hommey [:glandium]]

Floating point precision is not something I'd consider worth trading performance for. We've had rounding errors build up in the past, and that would surely make things worse. I'm convinced this would break at least some reftests.