[Mesa-dev] [PATCH] Revert "radeon/llvm: enable unsafe math for graphics shaders"

Matt Arsenault arsenm2 at gmail.com
Wed Feb 18 02:46:31 PST 2015


> On Feb 17, 2015, at 11:52 PM, Grigori Goronzy <greg at chown.ath.cx> wrote:
> 
> Hi,
> 
> AFAIR not enabling this makes LLVM generate really slow code in some
> common cases. Maybe this is just a bug in LLVM/R600 triggered by unsafe
> FP math optimization or some optimization is too eager. Other drivers do
> fine with these types of optimization.
> 
> What's the impact on performance with unsafe FP math disabled at this time?
> 
> Best regards
> Grigori


The exact reason should be found, since this should be OK.

Also, this should be setting no-nans-fp-math / no-infs-fp-math and whatever others there are. unsafe-fp-math should just be controlling other algebraic kinds of optimizations




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