We're sinking stores, which is a good thing, but in the process creating selects for the store address operand, which SROA/Mem2Reg can't look through, which caused serious regressions.
The real fix is in SROA, which I'll be looking into.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280470 91177308-0d34-0410-b5e6-96231b3b80d8