[clang] [llvm] [Clang][AArch64] Implement widening FMMLA intrinsics (PR #165282)

[via cfe-commits]

https://github.com/Lukacma approved this pull request.

LGTM. Just wait with merging this patch until ACLE is merged in case there are further changes there.

https://github.com/llvm/llvm-project/pull/165282