[llvm] [MachineLICM] Workaround - apply RegMasks conservatively (PR #95926)

[Pierre van Houtryve via llvm-commits]

================
@@ -0,0 +1,49 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 5
+# RUN: llc -mtriple=aarch64-unknown-linux-gnu -run-pass=greedy,machinelicm -verify-machineinstrs -debug -o - %s | FileCheck %s
+
+# FIXME: Running RA is needed otherwise it runs pre-RA LICM.
----------------
Pierre-vh wrote:

For some reason it only triggers if I run RA first, otherwise it seems `MRI->isSSA()` returns true and that's what it uses to determine whether it's pre or post RA

https://github.com/llvm/llvm-project/pull/95926