llvm-project

b2e2d8b3 - [RISCV] Enable scalable loop vectorization for zvfhmin/zvfbfmin (#115272)

[RISCV] Enable scalable loop vectorization for zvfhmin/zvfbfmin (#115272) This PR enables scalable loop vectorization for f16 with zvfhmin and bf16 with zvfbfmin. Enabling this was dependent on filling out the gaps for scalable zvfhmin/zvfbfmin codegen, but everything that the loop vectorizer might emit should now be handled. It does this by marking f16 and bf16 as legal in `isLegalElementTypeForRVV`. There are a few users of `isLegalElementTypeForRVV` that have already been enabled in other PRs: - `isLegalStridedLoadStore` #115264 - `isLegalInterleavedAccessType` #115257 - `isLegalMaskedLoadStore` #115145 - `isLegalMaskedGatherScatter` #114945 The remaining user is `isLegalToVectorizeReduction`. We can't promote f16/bf16 reductions to f32 so we need to disable them for scalable vectors. The cost model actually marks these as invalid, but for out-of-tree reductions `ComputeReductionResult` doesn't get costed and it will end up emitting a reduction intrinsic regardless, so we still need to mark them as illegal. We might be able to remove this restriction later for fmax and fmin reductions.