[PATCH] D86522: [RISC-V] Implement RISCVInstrInfo::isCopyInstrImpl()

[Alexander Richardson via Phabricator via llvm-commits]

arichardson updated this revision to Diff 289113.
arichardson added a comment.

Drop additional cases, keeping only the ones also listed in isAsCheapAsAMove().


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D86522/new/

https://reviews.llvm.org/D86522

Files:
  llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
  llvm/lib/Target/RISCV/RISCVInstrInfo.h


Index: llvm/lib/Target/RISCV/RISCVInstrInfo.h
===================================================================
--- llvm/lib/Target/RISCV/RISCVInstrInfo.h
+++ llvm/lib/Target/RISCV/RISCVInstrInfo.h
@@ -83,6 +83,9 @@
 
   bool isAsCheapAsAMove(const MachineInstr &MI) const override;
 
+  Optional<DestSourcePair>
+  isCopyInstrImpl(const MachineInstr &MI) const override;
+
   bool verifyInstruction(const MachineInstr &MI,
                          StringRef &ErrInfo) const override;
 
Index: llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
===================================================================
--- llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
+++ llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
@@ -530,6 +530,30 @@
   return MI.isAsCheapAsAMove();
 }
 
+Optional<DestSourcePair>
+RISCVInstrInfo::isCopyInstrImpl(const MachineInstr &MI) const {
+  if (MI.isMoveReg())
+    return DestSourcePair{MI.getOperand(0), MI.getOperand(1)};
+  switch (MI.getOpcode()) {
+  default:
+    break;
+  case RISCV::ADDI:
+  case RISCV::ORI:
+  case RISCV::XORI:
+    if (MI.getOperand(2).isImm() && MI.getOperand(2).getImm() == 0)
+      return DestSourcePair{MI.getOperand(0), MI.getOperand(1)};
+    break;
+  case RISCV::FSGNJ_D:
+  case RISCV::FSGNJ_S:
+    // The canonical floatig-point move is fsgnj rd, rs, rs.
+    if (MI.getOperand(1).isReg() && MI.getOperand(2).isReg() &&
+        MI.getOperand(1).getReg() == MI.getOperand(2).getReg())
+      return DestSourcePair{MI.getOperand(0), MI.getOperand(1)};
+    break;
+  }
+  return None;
+}
+
 bool RISCVInstrInfo::verifyInstruction(const MachineInstr &MI,
                                        StringRef &ErrInfo) const {
   const MCInstrInfo *MCII = STI.getInstrInfo();


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