[all-commits] [llvm/llvm-project] 396b6b: [RISCV] Recurse on second operand of two operand s...

[Philip Reames via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 396b6bbc5ecef93fce09d6463f47b44dc501d2aa
      https://github.com/llvm/llvm-project/commit/396b6bbc5ecef93fce09d6463f47b44dc501d2aa
  Author: Philip Reames <preames at rivosinc.com>
  Date:   2024-01-24 (Wed, 24 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-exact-vlen.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-shuffle-transpose.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-shufflevector-vnsrl.ll
    M llvm/test/CodeGen/RISCV/rvv/vector-deinterleave-fixed.ll

  Log Message:
  -----------
  [RISCV] Recurse on second operand of two operand shuffles (#79197)

This builds on bdc41106ee48dce59c500c9a3957af947f30c8c3.

This change completes the migration to a recursive shuffle lowering
strategy where when we encounter an unknown two argument shuffle, we
lower each operand as a single source permute, and then use a vselect
(i.e. a vmerge) to combine the results. This relies for code quality on
the post-isel combine which will aggressively fold that vmerge back into
the materialization of the second operand if possible.

Note: The change includes only the most immediately obvious of the
stylistic cleanup. There's a bunch of code movement that this enables
that I'll do as a separate patch as rolling it into this creates an
unreadable diff.