[PATCH] D107353: [LoopIdiom] let the pass deal with runtime memset size

Fri Aug 13 12:24:23 PDT 2021

efriedma added a comment.

In D107353#2944152 <https://reviews.llvm.org/D107353#2944152>, @lebedev.ri wrote:

> In D107353#2944144 <https://reviews.llvm.org/D107353#2944144>, @eopXD wrote:
>
>> No code for saturation here.
>> I thought restricting to address space zero prevents the need of saturation.
>
> @efriedma does that sound right?

I think I mentioned this on the other bug... but sounds right to me; overflow implies undefined behavior.  If the amount does overflow, that means the memset is writing at least once to every byte in the address space.  Among other things, that implies a store to null.

Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D107353/new/

https://reviews.llvm.org/D107353