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A REG_SEQUENCE instruction may use the same register twice. 

If we are emitting COPY instructions for the REG_SEQUENCE, make sure the kill
flag goes on the last COPY. Otherwise we may be using a killed register.

<rdar://problem/8287792>

llvm-svn: 110589
This commit is contained in:
Jakob Stoklund Olesen 2010-08-09 20:19:16 +00:00
parent 891f831963
commit 3fa110f227
1 changed files with 11 additions and 1 deletions
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12
llvm/lib/CodeGen/TwoAddressInstructionPass.cpp
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@ -1446,7 +1446,17 @@ bool TwoAddressInstructionPass::EliminateRegSequences() {
//
// If the REG_SEQUENCE doesn't kill its source, keeping live variables
// correctly up to date becomes very difficult. Insert a copy.
//
// Defer any kill flag to the last operand using SrcReg. Otherwise, we
// might insert a COPY that uses SrcReg after is was killed.
if (isKill)
for (unsigned j = i + 2; j < e; j += 2)
if (MI->getOperand(j).getReg() == SrcReg) {
MI->getOperand(j).setIsKill();
isKill = false;
break;
}
MachineBasicBlock::iterator InsertLoc = MI;
MachineInstr *CopyMI = BuildMI(*MI->getParent(), InsertLoc,
MI->getDebugLoc(), TII->get(TargetOpcode::COPY))