[llvm] AMDGPU GlobalISel Add64 support (PR #124763)

[Matt Arsenault via llvm-commits]

================
@@ -1,42 +1,59 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
----------------
arsenm wrote:

Should pre-commit switches to generated checks. Also this should have a run line with a reference target without the instruction 

https://github.com/llvm/llvm-project/pull/124763