[PATCH] D19075: mergefunc: avoid merge with loop metadata

[JF Bastien via llvm-commits]

jfb added a comment.

In http://reviews.llvm.org/D19075#405855, @hfinkel wrote:

> Do we not unqiue MDNodes? This seems like a lot of code for what I would have thought should be: Compare the pointer equality all MDNode operands except the first (because the first is the unique loop id).


mergefunc wants an ordering for what it compares, so pure equality isn't sufficient (although `cmpLoopOperandMetadata` does start with `L == R`). It needs to know how to order in a stable way, so we also can't just order based on pointer value.


http://reviews.llvm.org/D19075