[PATCH] D114988: [IR] `GetElementPtrInst`: per-index `inrange` support

[Bruno De Fraine via Phabricator via llvm-commits]

brunodf added a comment.

Sorry, I'm late to read this diff.

In D114988#3171000 <https://reviews.llvm.org/D114988#3171000>, @efriedma wrote:

> Consider the following:
>
>   struct S {
>       int a[3], b[3], c[3];
>   };
>   
>   int foo(S* s) {
>     return &s.a[3] == &s.b[0];
>   }
>
> The C standard says this returns 1; if you lower the address computation using inrange, it returns poison. I think?

Could you clarify how the C standard guarantees this will return 1? I think the standard allows padding between struct members a and b (even though I see very little reason to add padding here) so the comparison does not have a defined result.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D114988/new/

https://reviews.llvm.org/D114988