svn commit: r228801 - head

David Schultz das at FreeBSD.ORG
Sun Jan 1 02:04:43 UTC 2012

On Thu, Dec 22, 2011, Dimitry Andric wrote:
>   Remove -mfancy-math from LIB32CPUFLAGS for amd64.  It has been default
>   for our gcc since more than three years (see r181534, which is also in
>   stable/9 and stable/8).  This flag used to be for the benefit of the old
>   in-kernel math emulator, which was removed more than eight years ago.

Quite the opposite, actually.  gcc/freebsd used to be hard-coded to
use -mno-fancy-math-387 by default, which was really only appropriate for
FPUless x86 chips back when FreeBSD supported them.  The makefile
setting overrides the old gcc default.  The flag isn't "for the
benefit of the in-kernel math emulator"; it's actually to reap the
benefits of *not* having an in-kernel math emulator!

Do you know if clang has the correct default here, or if it picked up
trunk gcc's bogus default?  It doesn't seem to support the flag to
change the behavior, and it seems to default to -mno-fancy-math-387.
(The flag should only affect things when -ffast-math is also specified.)

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