[all-commits] [llvm/llvm-project] 90f916: [RISCV][InsertVSETVLI] Mutate prior vsetvli AVL if...

[Philip Reames via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 90f9168307293ef5278a212dee98c884ab0141cf
      https://github.com/llvm/llvm-project/commit/90f9168307293ef5278a212dee98c884ab0141cf
  Author: Philip Reames <preames at rivosinc.com>
  Date:   2022-12-15 (Thu, 15 Dec 2022)

  Changed paths:
    M llvm/lib/Target/RISCV/RISCVInsertVSETVLI.cpp
    M llvm/test/CodeGen/RISCV/rvv/fixed-vector-shuffle-reverse.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-masked-gather.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-reduction-fp.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-reduction-int.ll
    M llvm/test/CodeGen/RISCV/rvv/vreductions-int-vp.ll
    M llvm/test/CodeGen/RISCV/rvv/vreductions-int.ll

  Log Message:
  -----------
  [RISCV][InsertVSETVLI] Mutate prior vsetvli AVL if doing so allows us to remove a toggle

This extends the backwards walk to allow mutating the previous vsetvl's AVL value if it was not used by any instructions in between. In practice, this mostly benefits vmv.x.s and fvmv.f.s patterns since vector instructions which ignore VL are rare.

Differential Revision: https://reviews.llvm.org/D140048