Fix an issue where the two-address conversion pass incorrectly rewrites untied
operands to an early clobber register. This fixes <rdar://problem/9566076>.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132738 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/TwoAddressInstructionPass.cpp b/lib/CodeGen/TwoAddressInstructionPass.cpp
index 52ea872..f54d879 100644
--- a/lib/CodeGen/TwoAddressInstructionPass.cpp
+++ b/lib/CodeGen/TwoAddressInstructionPass.cpp
@@ -1125,6 +1125,7 @@
break; // The tied operands have been eliminated.
}
+ bool IsEarlyClobber = false;
bool RemovedKillFlag = false;
bool AllUsesCopied = true;
unsigned LastCopiedReg = 0;
@@ -1132,7 +1133,11 @@
for (unsigned tpi = 0, tpe = TiedPairs.size(); tpi != tpe; ++tpi) {
unsigned SrcIdx = TiedPairs[tpi].first;
unsigned DstIdx = TiedPairs[tpi].second;
- unsigned regA = mi->getOperand(DstIdx).getReg();
+
+ const MachineOperand &DstMO = mi->getOperand(DstIdx);
+ unsigned regA = DstMO.getReg();
+ IsEarlyClobber |= DstMO.isEarlyClobber();
+
// Grab regB from the instruction because it may have changed if the
// instruction was commuted.
regB = mi->getOperand(SrcIdx).getReg();
@@ -1196,15 +1201,17 @@
}
if (AllUsesCopied) {
- // Replace other (un-tied) uses of regB with LastCopiedReg.
- for (unsigned i = 0, e = mi->getNumOperands(); i != e; ++i) {
- MachineOperand &MO = mi->getOperand(i);
- if (MO.isReg() && MO.getReg() == regB && MO.isUse()) {
- if (MO.isKill()) {
- MO.setIsKill(false);
- RemovedKillFlag = true;
+ if (!IsEarlyClobber) {
+ // Replace other (un-tied) uses of regB with LastCopiedReg.
+ for (unsigned i = 0, e = mi->getNumOperands(); i != e; ++i) {
+ MachineOperand &MO = mi->getOperand(i);
+ if (MO.isReg() && MO.getReg() == regB && MO.isUse()) {
+ if (MO.isKill()) {
+ MO.setIsKill(false);
+ RemovedKillFlag = true;
+ }
+ MO.setReg(LastCopiedReg);
}
- MO.setReg(LastCopiedReg);
}
}