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

[Reid Kleckner via llvm-commits]

rnk accepted this revision.
rnk added a comment.
This revision is now accepted and ready to land.

lgtm, but let's bug Sanjoy, the person who seems to think the hardest about IPO function attrs right now.


http://reviews.llvm.org/D20555