using namespace llvm;
char ProcessImplicitDefs::ID = 0;
-static RegisterPass<ProcessImplicitDefs> X("processimpdefs",
- "Process Implicit Definitions.");
+INITIALIZE_PASS(ProcessImplicitDefs, "processimpdefs",
+ "Process Implicit Definitions.", false, false);
void ProcessImplicitDefs::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesCFG();
MachineFunctionPass::getAnalysisUsage(AU);
}
-bool ProcessImplicitDefs::CanTurnIntoImplicitDef(MachineInstr *MI,
- unsigned Reg, unsigned OpIdx,
- const TargetInstrInfo *tii_) {
- unsigned SrcReg, DstReg, SrcSubReg, DstSubReg;
- if (tii_->isMoveInstr(*MI, SrcReg, DstReg, SrcSubReg, DstSubReg) &&
- Reg == SrcReg && SrcSubReg == 0 && DstSubReg == 0)
- return true;
+bool
+ProcessImplicitDefs::CanTurnIntoImplicitDef(MachineInstr *MI,
+ unsigned Reg, unsigned OpIdx,
+ const TargetInstrInfo *tii_,
+ SmallSet<unsigned, 8> &ImpDefRegs) {
+ switch(OpIdx) {
+ case 1:
+ return MI->isCopy() && (MI->getOperand(0).getSubReg() == 0 ||
+ ImpDefRegs.count(MI->getOperand(0).getReg()));
+ case 2:
+ return MI->isSubregToReg() && (MI->getOperand(0).getSubReg() == 0 ||
+ ImpDefRegs.count(MI->getOperand(0).getReg()));
+ default: return false;
+ }
+}
- if (OpIdx == 2 && MI->isSubregToReg())
- return true;
- if (OpIdx == 1 && MI->isExtractSubreg())
- return true;
+static bool isUndefCopy(MachineInstr *MI, unsigned Reg,
+ const TargetInstrInfo *tii_,
+ SmallSet<unsigned, 8> &ImpDefRegs) {
+ if (MI->isCopy()) {
+ MachineOperand &MO0 = MI->getOperand(0);
+ MachineOperand &MO1 = MI->getOperand(1);
+ if (MO1.getReg() != Reg)
+ return false;
+ if (!MO0.getSubReg() || ImpDefRegs.count(MO0.getReg()))
+ return true;
+ return false;
+ }
return false;
}
continue;
}
- if (MI->isInsertSubreg()) {
- MachineOperand &MO = MI->getOperand(2);
- if (ImpDefRegs.count(MO.getReg())) {
- // %reg1032<def> = INSERT_SUBREG %reg1032, undef, 2
- // This is an identity copy, eliminate it now.
+ // Eliminate %reg1032:sub<def> = COPY undef.
+ if (MI->isCopy() && MI->getOperand(0).getSubReg()) {
+ MachineOperand &MO = MI->getOperand(1);
+ if (MO.isUndef() || ImpDefRegs.count(MO.getReg())) {
if (MO.isKill()) {
LiveVariables::VarInfo& vi = lv_->getVarInfo(MO.getReg());
vi.removeKill(MI);
bool ChangedToImpDef = false;
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
MachineOperand& MO = MI->getOperand(i);
- if (!MO.isReg() || !MO.isUse() || MO.isUndef())
+ if (!MO.isReg() || (MO.isDef() && !MO.getSubReg()) || MO.isUndef())
continue;
unsigned Reg = MO.getReg();
if (!Reg)
if (!ImpDefRegs.count(Reg))
continue;
// Use is a copy, just turn it into an implicit_def.
- if (CanTurnIntoImplicitDef(MI, Reg, i, tii_)) {
+ if (CanTurnIntoImplicitDef(MI, Reg, i, tii_, ImpDefRegs)) {
bool isKill = MO.isKill();
MI->setDesc(tii_->get(TargetOpcode::IMPLICIT_DEF));
for (int j = MI->getNumOperands() - 1, ee = 0; j > ee; --j)
Changed = true;
MO.setIsUndef();
+ // This is a partial register redef of an implicit def.
+ // Make sure the whole register is defined by the instruction.
+ if (MO.isDef()) {
+ MI->addRegisterDefined(Reg);
+ continue;
+ }
if (MO.isKill() || MI->isRegTiedToDefOperand(i)) {
// Make sure other uses of
for (unsigned j = i+1; j != e; ++j) {
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 && SrcSubReg == 0 && DstSubReg == 0) {
+ if (isUndefCopy(RMI, Reg, tii_, ImpDefRegs)) {
RMI->setDesc(tii_->get(TargetOpcode::IMPLICIT_DEF));
bool isKill = false;