[PATCH] D63215: Fixing @llvm.memcpy not honoring volatile

Thu Jun 13 01:52:25 PDT 2019

gchatelet added a comment.

In D63215#1541086 <https://reviews.llvm.org/D63215#1541086>, @gchatelet wrote:

> In D63215#1540160 <https://reviews.llvm.org/D63215#1540160>, @efriedma wrote:
>
> > What happens if findOptimalMemOpLowering fails?  We have other ways of lowering memcpy/memset that could also violate the "one store per byte" rule.
>
>
> Yes indeed, I need to take care of this as well.

So I've looked at the code, I believe the general case is covered.
What's left is the call to libc's memcpy (which is OK until the standard is updated) and the target specific code: nothing pops out particularly here but I'm not really qualified to review all of it.

BTW I'm not sure Intel's `rep movs` gives any guarantee on the overlapping access, it's microcoded nowadays.

Repository:
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  https://reviews.llvm.org/D63215/new/

https://reviews.llvm.org/D63215