Fix compiler warning about uninitialized variables. No functional change.

[oota-llvm.git] / lib / CodeGen / DeadMachineInstructionElim.cpp

diff --git a/lib/CodeGen/DeadMachineInstructionElim.cpp b/lib/CodeGen/DeadMachineInstructionElim.cpp
index 881df1e6b6673dd3f1d1041f439805c4d1f54972..4832a5ee9ae0488f37cd2e08c297f8742ae2bf61 100644 (file)
--- a/lib/CodeGen/DeadMachineInstructionElim.cpp
+++ b/lib/CodeGen/DeadMachineInstructionElim.cpp
@@ -16,6 +16,7 @@
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/Support/Compiler.h"
+#include "llvm/Support/Debug.h"
 #include "llvm/Target/TargetInstrInfo.h"
 #include "llvm/Target/TargetMachine.h"
 using namespace llvm;
@@ -57,7 +58,7 @@ bool DeadMachineInstructionElim::isDead(MachineInstr *MI) const {
   // Examine each operand.
   for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
     const MachineOperand &MO = MI->getOperand(i);
-    if (MO.isRegister() && MO.isDef()) {
+    if (MO.isReg() && MO.isDef()) {
       unsigned Reg = MO.getReg();
       if (TargetRegisterInfo::isPhysicalRegister(Reg) ?
           LivePhysRegs[Reg] : !MRI->use_empty(Reg)) {
@@ -109,6 +110,7 @@ bool DeadMachineInstructionElim::runOnMachineFunction(MachineFunction &MF) {
 
       // If the instruction is dead, delete it!
       if (isDead(MI)) {
+        DOUT << "DeadMachineInstructionElim: DELETING: " << *MI;
         AnyChanges = true;
         MI->eraseFromParent();
         MIE = MBB->rend();
@@ -120,13 +122,16 @@ bool DeadMachineInstructionElim::runOnMachineFunction(MachineFunction &MF) {
       // Record the physreg defs.
       for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
         const MachineOperand &MO = MI->getOperand(i);
-        if (MO.isRegister() && MO.isDef()) {
+        if (MO.isReg() && MO.isDef()) {
           unsigned Reg = MO.getReg();
           if (Reg != 0 && TargetRegisterInfo::isPhysicalRegister(Reg)) {
             LivePhysRegs.reset(Reg);
-            for (const unsigned *AliasSet = TRI->getAliasSet(Reg);
-                 *AliasSet; ++AliasSet)
-              LivePhysRegs.reset(*AliasSet);
+            // Check the subreg set, not the alias set, because a def
+            // of a super-register may still be partially live after
+            // this def.
+            for (const unsigned *SubRegs = TRI->getSubRegisters(Reg);
+                 *SubRegs; ++SubRegs)
+              LivePhysRegs.reset(*SubRegs);
           }
         }
       }
@@ -134,7 +139,7 @@ bool DeadMachineInstructionElim::runOnMachineFunction(MachineFunction &MF) {
       // both defined and used in the same instruction.
       for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
         const MachineOperand &MO = MI->getOperand(i);
-        if (MO.isRegister() && MO.isUse()) {
+        if (MO.isReg() && MO.isUse()) {
           unsigned Reg = MO.getReg();
           if (Reg != 0 && TargetRegisterInfo::isPhysicalRegister(Reg)) {
             LivePhysRegs.set(Reg);