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Diffstat (limited to 'lib/CodeGen/LiveVariables.cpp')
-rw-r--r--lib/CodeGen/LiveVariables.cpp28
1 files changed, 15 insertions, 13 deletions
diff --git a/lib/CodeGen/LiveVariables.cpp b/lib/CodeGen/LiveVariables.cpp
index ecfebc5511..a7bdbd92ff 100644
--- a/lib/CodeGen/LiveVariables.cpp
+++ b/lib/CodeGen/LiveVariables.cpp
@@ -335,7 +335,7 @@ bool LiveVariables::hasRegisterUseBelow(unsigned Reg,
return true;
}
-bool LiveVariables::HandlePhysRegKill(unsigned Reg) {
+bool LiveVariables::HandlePhysRegKill(unsigned Reg, MachineInstr *MI) {
if (!PhysRegUse[Reg] && !PhysRegDef[Reg])
return false;
@@ -373,8 +373,10 @@ bool LiveVariables::HandlePhysRegKill(unsigned Reg) {
}
}
}
- if (LastRefOrPartRef == PhysRegDef[Reg])
- // Not used at all.
+
+ if (LastRefOrPartRef == PhysRegDef[Reg] && LastRefOrPartRef != MI)
+ // If the last reference is the last def, then it's not used at all.
+ // That is, unless we are currently processing the last reference itself.
LastRefOrPartRef->addRegisterDead(Reg, TRI, true);
/* Partial uses. Mark register def dead and add implicit def of
@@ -427,14 +429,14 @@ void LiveVariables::HandlePhysRegDef(unsigned Reg, MachineInstr *MI) {
// Start from the largest piece, find the last time any part of the register
// is referenced.
- if (!HandlePhysRegKill(Reg)) {
+ if (!HandlePhysRegKill(Reg, MI)) {
// Only some of the sub-registers are used.
for (const unsigned *SubRegs = TRI->getSubRegisters(Reg);
unsigned SubReg = *SubRegs; ++SubRegs) {
if (!Live.count(SubReg))
// Skip if this sub-register isn't defined.
continue;
- if (HandlePhysRegKill(SubReg)) {
+ if (HandlePhysRegKill(SubReg, MI)) {
Live.erase(SubReg);
for (const unsigned *SS = TRI->getSubRegisters(SubReg); *SS; ++SS)
Live.erase(*SS);
@@ -475,7 +477,7 @@ void LiveVariables::HandlePhysRegDef(unsigned Reg, MachineInstr *MI) {
}
} else {
// Otherwise, the super register is killed.
- if (HandlePhysRegKill(SuperReg)) {
+ if (HandlePhysRegKill(SuperReg, MI)) {
PhysRegDef[SuperReg] = NULL;
PhysRegUse[SuperReg] = NULL;
for (const unsigned *SS = TRI->getSubRegisters(SuperReg); *SS; ++SS) {
@@ -558,13 +560,13 @@ bool LiveVariables::runOnMachineFunction(MachineFunction &mf) {
SmallVector<unsigned, 4> DefRegs;
for (unsigned i = 0; i != NumOperandsToProcess; ++i) {
const MachineOperand &MO = MI->getOperand(i);
- if (MO.isReg() && MO.getReg()) {
- unsigned MOReg = MO.getReg();
- if (MO.isUse())
- UseRegs.push_back(MOReg);
- if (MO.isDef())
- DefRegs.push_back(MOReg);
- }
+ if (!MO.isReg() || MO.getReg() == 0)
+ continue;
+ unsigned MOReg = MO.getReg();
+ if (MO.isUse())
+ UseRegs.push_back(MOReg);
+ if (MO.isDef())
+ DefRegs.push_back(MOReg);
}
// Process all uses.