[PATCH] D106790: prfchwintrin.h: Make _m_prefetchw take a pointer to volatile (PR49124)

Tue Jul 27 12:30:29 PDT 2021

rnk added a comment.

In D106790#2906762 <https://reviews.llvm.org/D106790#2906762>, @hans wrote:

> In D106790#2905110 <https://reviews.llvm.org/D106790#2905110>, @rnk wrote:
>
>> Does this match GCC? They also provide this Intel intrinsic.
>
> No, they define it without volatile (and also without const): https://github.com/gcc-mirror/gcc/blob/releases/gcc-11.1.0/gcc/config/i386/prfchwintrin.h#L32
>
> But maybe their header doesn't get included together with Microsoft's header?

Sure, they won't be included together, but will GCC users get warnings from passing non-volatile pointers to `_mm_prefetchw`? If we change these qualifiers to match MSVC, will GCC/Clang users be able to observe any change in behavior?

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https://reviews.llvm.org/D106790