[all-commits] [llvm/llvm-project] 09c3d1: [IA] Add support for [de]interleave{3, 5, 7} (#139373)

[Luke Lau via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 09c3d1432b15203762b6ccd8f2faec17b5c61c8c
      https://github.com/llvm/llvm-project/commit/09c3d1432b15203762b6ccd8f2faec17b5c61c8c
  Author: Luke Lau <luke at igalia.com>
  Date:   2025-05-22 (Thu, 22 May 2025)

  Changed paths:
    M llvm/include/llvm/CodeGen/TargetLowering.h
    M llvm/lib/CodeGen/InterleavedAccessPass.cpp
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-deinterleave-load.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-interleave-store.ll
    M llvm/test/CodeGen/RISCV/rvv/vector-deinterleave-load.ll
    M llvm/test/CodeGen/RISCV/rvv/vector-interleave-store.ll
    M llvm/test/CodeGen/RISCV/rvv/vp-vector-interleaved-access.ll
    M llvm/test/Transforms/InterleavedAccess/RISCV/interleaved-accesses.ll

  Log Message:
  -----------
  [IA] Add support for [de]interleave{3,5,7} (#139373)

This adds support for lowering deinterleave and interleave intrinsics
for factors 3 5 and 7 into target specific memory intrinsics.

Notably this doesn't add support for handling higher factors constructed
from interleaving interleave intrinsics, e.g. factor 6 from interleave3
+ interleave2.

I initially tried this but it became very complex very quickly. For
example, because there's now multiple factors involved
interleaveLeafValues is no longer symmetric between interleaving and
deinterleaving. There's then also two ways of representing a factor 6
deinterleave: It can both be done as either 1 deinterleave3 and 3
deinterleave2s OR 1 deinterleave2 and 3 deinterleave3s.

I'm not sure the complexity of supporting arbitrary factors is warranted
given how we only need to support a small number of factors currently:
SVE only needs factors 2,3,4 whilst RVV only needs 2,3,4,5,6,7,8.

My preference would be to just add a interleave6 and deinterleave6
intrinsic to avoid all this ambiguity, but I'll defer this discussion to
a later patch.



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