commuteInstr() can now commute non-ssa machine instrs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47043 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 9 insertions, 0 deletions

diff --git a/lib/CodeGen/TargetInstrInfoImpl.cpp b/lib/CodeGen/TargetInstrInfoImpl.cpp
index cd2bfcce02..598b94af9c 100644
--- a/lib/CodeGen/TargetInstrInfoImpl.cpp
+++ b/lib/CodeGen/TargetInstrInfoImpl.cpp
@@ -23,8 +23,17 @@ MachineInstr *TargetInstrInfoImpl::commuteInstruction(MachineInstr *MI) const {
          "This only knows how to commute register operands so far");
   unsigned Reg1 = MI->getOperand(1).getReg();
   unsigned Reg2 = MI->getOperand(2).getReg();
+  MachineOperand &MO = MI->getOperand(0);
+  bool UpdateReg0 = MO.isReg() && MO.getReg() == Reg1;
   bool Reg1IsKill = MI->getOperand(1).isKill();
   bool Reg2IsKill = MI->getOperand(2).isKill();
+  if (UpdateReg0) {
+    // Must be two address instruction!
+    assert(MI->getDesc().getOperandConstraint(0, TOI::TIED_TO) &&
+           "Expecting a two-address instruction!");
+    Reg2IsKill = false;
+    MI->getOperand(0).setReg(Reg2);
+  }
   MI->getOperand(2).setReg(Reg1);
   MI->getOperand(1).setReg(Reg2);
   MI->getOperand(2).setIsKill(Reg1IsKill);