[PATCH] D50233: [InstCombine] Transform str(n)cmp to memcmp

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

> But that also implies that you have to emit an inline implementation since you might not control what the implementation of memcmp supplied by libc does?

Assuming there isn't a data race, the libc implementation of memcmp can't actually do anything undefined.  In assembly, "uninitialized" data always has some fixed value.

-------------

Given the problems here, we probably want to move this transform to the ExpandMemCmp pass, and only transform when we'll expand the compare inline.


Repository:
  rL LLVM

https://reviews.llvm.org/D50233