[llvm] Constant Fold Logf128 calls (PR #84501)

[David Green via llvm-commits]

davemgreen wrote:

That sounds like the same issue we were trying to solve (depending on what logl means on the given target). There is a commit in https://github.com/llvm/llvm-project/pull/96287 and https://github.com/llvm/llvm-project/pull/104929 that got so very close, in that I believe it was working on all the buildbots. This can cause a really surprising perf swing on AArch64 where soft-float routines get called, so it would be good if we can get something fixed.

https://github.com/llvm/llvm-project/pull/84501