llvm-project

71a0b9fd - [LAA] Allow vectorizing `A[NonZeroNonConstantStride*I] += 1`

[LAA] Allow vectorizing `A[NonZeroNonConstantStride*I] += 1` In this patch only do that when we can statically prove that non-constant stride is non-zero and the resulting index doesn't overflow. That can later be extended to introduce run-time check when not provable in compile-time. My main motivation for this is to move unit-strideness speculation to a VPlan-based transformation. However, it cannot be done right now because sometimes such speculation affects legality and we simply avoid vectorizing loop if it's not done. As such, we need to extend LAA to properly support dependence analysis/RT checks for strided access without speculating for it being one. This PR is expected to be the first one on that journey.