Re-apply 103156 and 103157. 103156 didn't break anything. 10315 exposed a coalescer bug that's fixed by 103170.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103172 91177308-0d34-0410-b5e6-96231b3b80d8
7 files changed