[llvm] [AMDGPU] Waterfall loop codegen improvement in SIInstrInfo (PR #192415)

[via llvm-commits]

gretay-amd wrote:

> > I have just pushed a tentative fix: add `_term` versions of `V_CMPX_EQ_*` Machine IR instructions and use them in the current PR.
> 
> Maybe we don't even need non-terminator versions of V_CMPX instructions, since they always write to EXEC?

Are you suggesting a change to all `V_CMPX*` instruction definitions not specific to this PR?  It is causing some test failures, probably minor issues. Would  you like me to make a separate PR for it? 

https://github.com/llvm/llvm-project/pull/192415