[PATCH] D71726: Let clang atomic builtins fetch add/sub support floating point types

[Artem Belevich via Phabricator via cfe-commits]

tra added inline comments.


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Comment at: clang/include/clang/Basic/TargetInfo.h:1418
+  /// Whether floating point atomic fetch add/sub is supported.
+  virtual bool isFPAtomicFetchAddSubSupported() const { return false; }
+
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yaxunl wrote:
> tra wrote:
> > I think it should be predicated on specific type.
> > E.g. NVPTX supports atomic ops on fp32 ~everywhere, but fp64 atomic add/sub is only supported on newer GPUs.
> > And then there's fp16...
> will do and add tests for fp16
The number of bits alone may not be sufficient to differentiate the FP variants.
E.g. 16-bit floats currently have 2 variants: IEEE FP16 and BFloat16 (supported by intel and newer NVIDIA GPUs).
CUDA-11 has introduced TF32 FP format, so we're likely to have more than one 32-bit FP type, too.
I think PPC has an odd `long double` variant represented as pair of 64-bit doubles.



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  https://reviews.llvm.org/D71726/new/

https://reviews.llvm.org/D71726