AMDGPU: Fix post-RA verifier errors with trackLivenessAfterRegAlloc

The condition reg of the cndmask_b64 expansion can't be killed by
the first one, and the implicit super register implicit def is needed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@272554 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed