[all-commits] [llvm/llvm-project] bdc411: [RISCV] Recurse on first operand of two operand sh...

[Philip Reames via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: bdc41106ee48dce59c500c9a3957af947f30c8c3
      https://github.com/llvm/llvm-project/commit/bdc41106ee48dce59c500c9a3957af947f30c8c3
  Author: Philip Reames <preames at rivosinc.com>
  Date:   2024-01-23 (Tue, 23 Jan 2024)

  Changed paths:
    M llvm/lib/Target/RISCV/RISCVISelLowering.cpp
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-fp-interleave.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-int-interleave.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-int-shuffles.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-interleaved-access.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-shuffle-transpose.ll

  Log Message:
  -----------
  [RISCV] Recurse on first operand of two operand shuffles (#79180)

This is the first step towards an alternate shuffle lowering design for
the general two vector argument case. The goal is to leverage the
existing lowering for single vector permutes to avoid as many of the
vrgathers as required - even if we do need the other.

This patch handles only the first argument, and is arguably a slightly
weird half-step. However, the test changes from the full two argument
recurse patch are a lot harder to reason about. Taking this half step
gives much more easily reviewable changes, and is thus worthwhile. I
intend to post the patch for the second argument once this has landed.