If the first definition of a virtual register is a partial redef, add an

<imp-def> operand for the full register. This ensures that the full physical
register is marked live after register allocation.

llvm-svn: 104320

1 files changed, 15 insertions, 5 deletions

diff --git a/llvm/lib/CodeGen/MachineInstr.cpp b/llvm/lib/CodeGen/MachineInstr.cpp
index 553b13938c9..595fddda6f6 100644
--- a/llvm/lib/CodeGen/MachineInstr.cpp
+++ b/llvm/lib/CodeGen/MachineInstr.cpp
@@ -1388,11 +1388,21 @@ bool MachineInstr::addRegisterDead(unsigned IncomingReg,
 
 void MachineInstr::addRegisterDefined(unsigned IncomingReg,
                                       const TargetRegisterInfo *RegInfo) {
-  MachineOperand *MO = findRegisterDefOperand(IncomingReg, false, RegInfo);
-  if (!MO || MO->getSubReg())
-    addOperand(MachineOperand::CreateReg(IncomingReg,
-                                         true  /*IsDef*/,
-                                         true  /*IsImp*/));
+  if (TargetRegisterInfo::isPhysicalRegister(IncomingReg)) {
+    MachineOperand *MO = findRegisterDefOperand(IncomingReg, false, RegInfo);
+    if (MO)
+      return;
+  } else {
+    for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
+      const MachineOperand &MO = getOperand(i);
+      if (MO.isReg() && MO.getReg() == IncomingReg && MO.isDef() &&
+          MO.getSubReg() == 0)
+        return;
+    }
+  }
+  addOperand(MachineOperand::CreateReg(IncomingReg,
+                                       true  /*IsDef*/,
+                                       true  /*IsImp*/));
 }
 
 unsigned