Avoid deleting extra copies when RegistersDefinedFromSameValue is true.

This function adds copies to be erased to DupCopies, avoid also adding
them to DeadCopies.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157147 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed