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Fix a case where debug_value could affect codegen. 

llvm-svn: 94866
This commit is contained in:
Dale Johannesen 2010-01-30 00:57:47 +00:00
parent b0fe9b9a40
commit e057403835
1 changed files with 12 additions and 0 deletions
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12
llvm/lib/CodeGen/RegAllocLocal.cpp
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@ -838,6 +838,18 @@ void RALocal::AllocateBasicBlock(MachineBasicBlock &MBB) {
}
}
// If a DEBUG_VALUE says something is located in a spilled register,
// change the DEBUG_VALUE to be undef, which prevents the register
// from being reloaded here. Doing that would change the generated
// code, unless another use immediately follows this instruction.
if (MI->getOpcode()==TargetInstrInfo::DEBUG_VALUE &&
MI->getNumOperands()==3 && MI->getOperand(0).isReg()) {
unsigned VirtReg = MI->getOperand(0).getReg();
if (VirtReg && TargetRegisterInfo::isVirtualRegister(VirtReg) &&
!getVirt2PhysRegMapSlot(VirtReg))
MI->getOperand(0).setReg(0U);
}
// Get the used operands into registers. This has the potential to spill
// incoming values if we are out of registers. Note that we completely
// ignore physical register uses here. We assume that if an explicit