[PATCH] D77013: [AMDGPU] Add options -mamdgpu-ieee -mno-amdgpu-ieee

[Yaxun Liu via Phabricator via cfe-commits]

yaxunl marked 2 inline comments as done.
yaxunl added inline comments.


================
Comment at: clang/lib/Frontend/CompilerInvocation.cpp:1951
+      Args.hasFlag(options::OPT_mamdgpu_ieee, options::OPT_mno_amdgpu_ieee,
+                   !LangOptsRef.NoHonorNaNs);
+
----------------
arsenm wrote:
> yaxunl wrote:
> > arsenm wrote:
> > > This should not be implied by no honor nans. This is an ABI changing option. We need to require that no nans FP math is enabled to use this mode correctly though
> > OK I plan to make changes about this. However I need to clarify about when should we add function attribute amdgpu-ieee=false:
> > 
> > 1. when neither -mamdgpu-ieee nor -mno-amdgpu-ieee is specified, we will add func attr amdgpu-ieee=false if LangOptsRef.NoHonorNaNs is true
> > 
> > 2. when -mamdgpu-ieee or -mno-amdgpu-ieee is specified, we will add func attr amdgpu-ieee=false solely based on these two options, disregarding LangOptsRef.NoHonorNaNs
> > 
> > Is that correct?
>   # You should only add the attribute "amdgpu-ieee"="false" if and only if -mno-amdgpu-ieee is used. This is entirely orthogonal to NoHonorNaNs. The default is amdgpu-ieee=true, and there's no need to explicitly mark the function
> 
>   # It is an error to use -mno-amdgpu-ieee without NoHonorNaNs because we do not implement the legalization required to manually quiet signaling nans. We cannot silently drop the use of of this
> 
I can add diagnostics in clang -cc1 when -mno-amdgpu-ieee is used without NoHonorNaNs. I cannot diagnose it in clang driver because there are multiple driver options affecting NoHonorNaNs and they could override each other.


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  https://reviews.llvm.org/D77013/new/

https://reviews.llvm.org/D77013