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>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110589 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen 2010-08-09 20:19:16 +00:00
parent 9de1ac267e
commit e4b9c4f187

View File

@ -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))