[PATCH] D129757: [RISCV] Optimize SELECT_CC when the true value of select is Constant

[Liao Chunyu via Phabricator via llvm-commits]

liaolucy updated this revision to Diff 445672.
liaolucy added a comment.

1. Address @frasercrmck's comments
2. Address @asb's comments. Fix negative optimization of 20100416-1.c from the GCC torture suite. No optimization is required when TrueV and FalseV are both constants.

selectcc-to-shiftand.ll has an example already covering this type.
define i32 @pos_sel_constants(i32 signext %a) {
; CHECK-LABEL: pos_sel_constants:
; CHECK:       # %bb.0:
; CHECK-NEXT:    mv a1, a0
; CHECK-NEXT:    li a0, 5
; CHECK-NEXT:    bgez a1, .LBB4_2
; CHECK-NEXT:  # %bb.1:
; CHECK-NEXT:    li a0, 0
; CHECK-NEXT:  .LBB4_2:
; CHECK-NEXT:    ret

  %tmp.1 = icmp sgt i32 %a, -1
  %retval = select i1 %tmp.1, i32 5, i32 0
  ret i32 %retval

}


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D129757/new/

https://reviews.llvm.org/D129757

Files:
  llvm/lib/Target/RISCV/RISCVISelLowering.cpp
  llvm/test/CodeGen/RISCV/double-convert-strict.ll
  llvm/test/CodeGen/RISCV/double-convert.ll
  llvm/test/CodeGen/RISCV/float-convert-strict.ll
  llvm/test/CodeGen/RISCV/float-convert.ll
  llvm/test/CodeGen/RISCV/fpclamptosat.ll
  llvm/test/CodeGen/RISCV/fpclamptosat_vec.ll
  llvm/test/CodeGen/RISCV/half-convert-strict.ll
  llvm/test/CodeGen/RISCV/half-convert.ll
  llvm/test/CodeGen/RISCV/rv32zbb-zbp-zbkb.ll
  llvm/test/CodeGen/RISCV/rv32zbs.ll
  llvm/test/CodeGen/RISCV/rv64zbb.ll
  llvm/test/CodeGen/RISCV/uadd_sat.ll
  llvm/test/CodeGen/RISCV/uadd_sat_plus.ll
  llvm/test/CodeGen/RISCV/usub_sat.ll
  llvm/test/CodeGen/RISCV/usub_sat_plus.ll

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