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Don't set kill flags on uses of CopyFromReg nodes. InstrEmitter doesn't

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create separate virtual registers for CopyFromReg values, so uses of
them don't necessarily kill the value.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103519 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2010-05-11 21:59:14 +00:00
parent 9647f3d981
commit 9d7019f586
1 changed files with 16 additions and 9 deletions
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25
lib/CodeGen/SelectionDAG/InstrEmitter.cpp
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@ -297,15 +297,22 @@ InstrEmitter::AddRegisterOperand(MachineInstr *MI, SDValue Op,
}
// If this value has only one use, that use is a kill. This is a
// conservative approximation. Tied operands are never killed, so we need
// to check that. And that means we need to determine the index of the
// operand.
unsigned Idx = MI->getNumOperands();
while (Idx > 0 &&
MI->getOperand(Idx-1).isReg() && MI->getOperand(Idx-1).isImplicit())
--Idx;
bool isTied = MI->getDesc().getOperandConstraint(Idx, TOI::TIED_TO) != -1;
bool isKill = Op.hasOneUse() && !isTied && !IsDebug;
// conservative approximation. InstrEmitter does trivial coalescing
// with CopyFromReg nodes, so don't emit kill flags for them.
// Tied operands are never killed, so we need to check that. And that
// means we need to determine the index of the operand.
bool isKill = Op.hasOneUse() &&
Op.getNode()->getOpcode() != ISD::CopyFromReg &&
!IsDebug;
if (isKill) {
unsigned Idx = MI->getNumOperands();
while (Idx > 0 &&
MI->getOperand(Idx-1).isReg() && MI->getOperand(Idx-1).isImplicit())
--Idx;
bool isTied = MI->getDesc().getOperandConstraint(Idx, TOI::TIED_TO) != -1;
if (isTied)
isKill = false;
}
MI->addOperand(MachineOperand::CreateReg(VReg, isOptDef,
false/*isImp*/, isKill,