[llvm] [AMDGPU] Fix subtarget predicates for some V_MAD, V_FMA and V_DOT instructions. (PR #71194)

[Ivan Kosarev via llvm-commits]

kosarev wrote:

> How do you find these problems? Once they are all fixed can you add some kind of assertion somewhere to stop them reoccuring?

I use the ambiguity checks in AsmMatcherEmitter, but it also takes making local changes manually teaching it about which of our predicates are mutually exclusive. I do hope to be able to make it catching that sort of problems without manual help at some point later (as part of https://github.com/llvm/llvm-project/issues/69256), but it currently feels like a long way to go.

https://github.com/llvm/llvm-project/pull/71194