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ProcessImplicitDefs should watch out for invalidated iterator and extra implicit operands on copies.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89880 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng
2009-11-25 21:13:39 +00:00
parent de9b1dae37
commit e7c9195706
2 changed files with 101 additions and 14 deletions
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59
lib/CodeGen/ProcessImplicitDefs.cpp
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@ -75,10 +75,11 @@ bool ProcessImplicitDefs::runOnMachineFunction(MachineFunction &fn) {
SmallSet<unsigned, 8> ImpDefRegs;
SmallVector<MachineInstr*, 8> ImpDefMIs;
MachineBasicBlock *Entry = fn.begin();
SmallVector<MachineInstr*, 4> RUses;
SmallPtrSet<MachineBasicBlock*,16> Visited;
SmallPtrSet<MachineInstr*, 8> ModInsts;
MachineBasicBlock *Entry = fn.begin();
for (df_ext_iterator<MachineBasicBlock*, SmallPtrSet<MachineBasicBlock*,16> >
DFI = df_ext_begin(Entry, Visited), E = df_ext_end(Entry, Visited);
DFI != E; ++DFI) {
@ -197,38 +198,68 @@ bool ProcessImplicitDefs::runOnMachineFunction(MachineFunction &fn) {
MI->eraseFromParent();
Changed = true;
// Process each use instruction once.
for (MachineRegisterInfo::use_iterator UI = mri_->use_begin(Reg),
UE = mri_->use_end(); UI != UE; ) {
MachineOperand &RMO = UI.getOperand();
UE = mri_->use_end(); UI != UE; ++UI) {
MachineInstr *RMI = &*UI;
++UI;
if (ModInsts.count(RMI))
continue;
MachineBasicBlock *RMBB = RMI->getParent();
if (RMBB == MBB)
continue;
if (ModInsts.insert(RMI))
RUses.push_back(RMI);
}
for (unsigned i = 0, e = RUses.size(); i != e; ++i) {
MachineInstr *RMI = RUses[i];
// Turn a copy use into an implicit_def.
unsigned SrcReg, DstReg, SrcSubReg, DstSubReg;
if (tii_->isMoveInstr(*RMI, SrcReg, DstReg, SrcSubReg, DstSubReg) &&
Reg == SrcReg) {
if (RMO.isKill()) {
RMI->setDesc(tii_->get(TargetInstrInfo::IMPLICIT_DEF));
bool isKill = false;
SmallVector<unsigned, 4> Ops;
for (unsigned j = 0, ee = RMI->getNumOperands(); j != ee; ++j) {
MachineOperand &RRMO = RMI->getOperand(j);
if (RRMO.isReg() && RRMO.getReg() == Reg) {
Ops.push_back(j);
if (RRMO.isKill())
isKill = true;
}
}
// Leave the other operands along.
for (unsigned j = 0, ee = Ops.size(); j != ee; ++j) {
unsigned OpIdx = Ops[j];
RMI->RemoveOperand(OpIdx-j);
}
// Update LiveVariables varinfo if the instruction is a kill.
if (isKill) {
LiveVariables::VarInfo& vi = lv_->getVarInfo(Reg);
vi.removeKill(RMI);
}
RMI->setDesc(tii_->get(TargetInstrInfo::IMPLICIT_DEF));
for (int j = RMI->getNumOperands() - 1, ee = 0; j > ee; --j)
RMI->RemoveOperand(j);
ModInsts.insert(RMI);
continue;
}
// Replace Reg with a new vreg that's marked implicit.
const TargetRegisterClass* RC = mri_->getRegClass(Reg);
unsigned NewVReg = mri_->createVirtualRegister(RC);
RMO.setReg(NewVReg);
RMO.setIsUndef();
RMO.setIsKill();
bool isKill = true;
for (unsigned j = 0, ee = RMI->getNumOperands(); j != ee; ++j) {
MachineOperand &RRMO = RMI->getOperand(j);
if (RRMO.isReg() && RRMO.getReg() == Reg) {
RRMO.setReg(NewVReg);
RRMO.setIsUndef();
if (isKill) {
// Only the first operand of NewVReg is marked kill.
RRMO.setIsKill();
isKill = false;
}
}
}
}
RUses.clear();
}
ModInsts.clear();
ImpDefRegs.clear();