[PATCH] D20555: [MemCpyOpt] Be conservative in the face of returns_twice calls

[Sanjoy Das via llvm-commits]

sanjoy added a comment.

I'm fine being bugged, but I think this review is missing some context -- how is "volatile stores escape the location being stored to" related to how we handle `setjmp` / `longjmp`?

A explicit test case on why we need this new rule will also be helpful (if not as a test case, then an example in the commit message), since `@test_volatile` only checks that we implement the rule correctly, but does not explain what the motivation is.


http://reviews.llvm.org/D20555