[llvm] [Passes] Always run LowerMatrixIntrinsics, request EarlyCSE on demand. (PR #118507)

[Nikita Popov via llvm-commits]

https://github.com/nikic commented:

We should definitely make sure that this is free for `O0`. A lot of the intrinsic lowering has been consolidated into PreISelIntrinsicLowering nowadays, so that we only need to scan once over all functions in the module. Maybe matrix intrinsic lowering for O0 can integrate there?

Alternatively, I vaguely remember that you had some kind of prototype a long time ago that allowed querying presence of certain intrinsics efficiently (I think even with this use in mind?)

https://github.com/llvm/llvm-project/pull/118507