[llvm-dev] Potentially unsafe loop optimization

[Richard Kenner via llvm-dev]

> Looks like the expand memcmp pass expanded the bcmp. Then ran
> InstructionSimplify on every basic block in the function because a
> change was made. That decided that the compare was always false. But
> I'm not sure it had anything to do with the bcmp expansion.

But that's not the relevant compare.  That compare is actually
provably false (abort is never called).  The compare that's at issue
is the loop end compare.