[llvm-branch-commits] [llvm] Reland "RegisterCoalescer: Add implicit-def of super register when coalescing SUBREG_TO_REG" (PR #134408)

[Sander de Smalen via llvm-branch-commits]

sdesmalen-arm wrote:

@arsenm are you happy for me to reland this?

I've done better testing this time around; doing a two-stage build with sanitisers enabled and running LNT on both X86 and AArch64 platforms.

https://github.com/llvm/llvm-project/pull/134408