[Openmp-commits] [PATCH] D62393: [OPENMP][NVPTX]Mark parallel level counter as volatile.

Alexey Bataev via Phabricator via Openmp-commits openmp-commits at lists.llvm.org
Tue Jun 11 16:05:38 PDT 2019

ABataev added a comment.

In D62393#1539040 <https://reviews.llvm.org/D62393#1539040>, @hfinkel wrote:

> In D62393#1539014 <https://reviews.llvm.org/D62393#1539014>, @ABataev wrote:
> > In D62393#1539012 <https://reviews.llvm.org/D62393#1539012>, @jfb wrote:
> >
> > > FWIW we already support `-fms-volatile`, so there's precedent if you wanted `-fnv-volatile` (however terrible that is).
> >
> >
> > Most probably, we don't need this option, clang should emit correct code for volatile vars in Cuda mode automatically.
> +1
> That having been said, maybe this is a very simple change because it is the same as (or very similar to) what MSVolatile does?
>   /// An LValue is a candidate for having its loads and stores be made atomic if
>   /// we are operating under /volatile:ms *and* the LValue itself is volatile and
>   /// performing such an operation can be performed without a libcall.
>   bool CodeGenFunction::LValueIsSuitableForInlineAtomic(LValue LV) {
>     if (!CGM.getCodeGenOpts().MSVolatile) return false;
>     AtomicInfo AI(*this, LV);
>     bool IsVolatile = LV.isVolatile() || hasVolatileMember(LV.getType());
>     // An atomic is inline if we don't need to use a libcall.
>     bool AtomicIsInline = !AI.shouldUseLibcall();
>     // MSVC doesn't seem to do this for types wider than a pointer.
>     if (getContext().getTypeSize(LV.getType()) >
>         getContext().getTypeSize(getContext().getIntPtrType()))
>       return false;
>     return IsVolatile && AtomicIsInline;
>   }
> Making this return true for when LangOpts.CUDAIsDevice might essentially do what we need?

Better to ask @tra or @jlebar. Maybe, clang already does something similar for Cuda?

  rOMP OpenMP



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