[all-commits] [llvm/llvm-project] faa326: [RISCV] Add branch+c.mv macrofusion for sifive-p45...

[Craig Topper via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: faa326de97bf6119dcc42806b07f3523c521ae96
      https://github.com/llvm/llvm-project/commit/faa326de97bf6119dcc42806b07f3523c521ae96
  Author: Craig Topper <craig.topper at sifive.com>
  Date:   2024-01-08 (Mon, 08 Jan 2024)

  Changed paths:
    M llvm/lib/Target/RISCV/RISCVExpandPseudoInsts.cpp
    M llvm/lib/Target/RISCV/RISCVFeatures.td
    M llvm/lib/Target/RISCV/RISCVISelLowering.cpp
    M llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
    M llvm/lib/Target/RISCV/RISCVInstrInfo.td
    M llvm/lib/Target/RISCV/RISCVProcessors.td
    M llvm/lib/Target/RISCV/RISCVSubtarget.h
    A llvm/test/CodeGen/RISCV/cmov-branch-opt.ll

  Log Message:
  -----------
  [RISCV] Add branch+c.mv macrofusion for sifive-p450. (#76169)

sifive-p450 supports a very restricted version of the short forward
branch optimization from the sifive-7-series.

For sifive-p450, a branch over a single c.mv can be macrofused as a
conditional move operation. Due to encoding restrictions on c.mv, we
can't conditionally move from X0. That would require c.li instead.