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Ignore <undef> uses when analyzing and rewriting.

llvm-svn: 125226
This commit is contained in:
Jakob Stoklund Olesen 2011-02-09 21:52:09 +00:00
parent 9f7beb42a8
commit 5c13598fd7

View File

@ -64,8 +64,12 @@ bool SplitAnalysis::canAnalyzeBranch(const MachineBasicBlock *MBB) {
/// analyzeUses - Count instructions, basic blocks, and loops using CurLI.
void SplitAnalysis::analyzeUses() {
const MachineRegisterInfo &MRI = MF.getRegInfo();
for (MachineRegisterInfo::reg_iterator I = MRI.reg_begin(CurLI->reg);
MachineInstr *MI = I.skipInstruction();) {
for (MachineRegisterInfo::reg_iterator I = MRI.reg_begin(CurLI->reg),
E = MRI.reg_end(); I != E; ++I) {
MachineOperand &MO = I.getOperand();
if (MO.isUse() && MO.isUndef())
continue;
MachineInstr *MI = MO.getParent();
if (MI->isDebugValue() || !UsingInstrs.insert(MI))
continue;
UseSlots.push_back(LIS.getInstructionIndex(MI).getDefIndex());
@ -918,6 +922,14 @@ void SplitEditor::rewriteAssigned() {
MO.setReg(0);
continue;
}
// <undef> operands don't really read the register, so just assign them to
// the complement.
if (MO.isUse() && MO.isUndef()) {
MO.setReg(Edit.get(0)->reg);
continue;
}
SlotIndex Idx = LIS.getInstructionIndex(MI);
Idx = MO.isUse() ? Idx.getUseIndex() : Idx.getDefIndex();