AMDGPU: Fold icmp/fcmp into icmp intrinsic

The typical use is a library vote function which
compares to 0. Fold the user condition into the intrinsic.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297650 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed