PR13578: Teach MachineCSE that instructions that use a constant register can be CSE'd safely.

This is common e.g. when doing rip-relative addressing on x86_64.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161728 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed