[PATCH] D39812: [Driver, CodeGen] pass through and apply -fassociative-math

Warren Ristow via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Wed Nov 8 11:44:40 PST 2017

wristow added a comment.

In https://reviews.llvm.org/D39812#919687, @spatel wrote:

> I just reviewed the gcc docs:
>  https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html
> "[-fassociative-math] requires that both -fno-signed-zeros and -fno-trapping-math be in effect."
> If we want to match that behavior, I need to change this patch to light up 'nsz' and the no-trapping-math function attribute.

Yes, I think we want to match that behavior.  But by "light up" 'nsz' and the no-trapping-math attribute, do you mean automatically turn them on when '-fassociative-math' is specified?  I'd think it should be the other way around: Suppress the effect of '-fassociative-math' unless both '-fno-signed-zeros' and '-fno-trapping-math' are also specified.


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