Functions with differing phis should not be merged.

Check that the incoming blocks of phi nodes are identical, and block
function merging if they are not.

rdar://problem/26255167

Differential Revision: http://reviews.llvm.org/D20462

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270250 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed