AU.addPreserved<LiveVariables>();
AU.addPreservedID(MachineLoopInfoID);
AU.addPreservedID(MachineDominatorsID);
- AU.addPreservedID(PHIEliminationID);
MachineFunctionPass::getAnalysisUsage(AU);
}
// If any of the definitions are used by another instruction between the
// position and the kill use, then it's not safe to sink it.
- //
+ //
// FIXME: This can be sped up if there is an easy way to query whether an
// instruction is before or after another instruction. Then we can use
// MachineRegisterInfo def / use instead.
KillMO->setIsKill(false);
KillMO = MI->findRegisterUseOperand(SavedReg, false, TRI);
KillMO->setIsKill(true);
-
+
if (LV)
LV->replaceKillInstruction(SavedReg, KillMI, MI);
continue; // Current use.
OtherUse = true;
// There is at least one other use in the MBB that will clobber the
- // register.
+ // register.
if (isTwoAddrUse(UseMI, Reg))
return true;
}
// %reg1029<def> = MOV8rr %reg1028
// %reg1029<def> = SHR8ri %reg1029, 7, %EFLAGS<imp-def,dead>
// insert => %reg1030<def> = MOV8rr %reg1029
- // %reg1030<def> = ADD8rr %reg1029<kill>, %reg1028<kill>, %EFLAGS<imp-def,dead>
+ // %reg1030<def> = ADD8rr %reg1029<kill>, %reg1028<kill>, %EFLAGS<imp-def,dead>
if (!MI->killsRegister(regC))
return false;
MachineBasicBlock::iterator &nmi,
unsigned Reg) {
MachineInstr *MI = &*mi;
- DenseMap<MachineInstr*, unsigned>::iterator DI = DistanceMap.find(MI);
+ DenseMap<MachineInstr*, unsigned>::iterator DI = DistanceMap.find(MI);
if (DI == DistanceMap.end())
// Must be created from unfolded load. Don't waste time trying this.
return false;
if (LV) {
for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
MachineOperand &MO = MI.getOperand(i);
- if (MO.isReg() &&
+ if (MO.isReg() &&
TargetRegisterInfo::isVirtualRegister(MO.getReg())) {
if (MO.isUse()) {
if (MO.isKill()) {
bool MadeChange = false;
DEBUG(dbgs() << "********** REWRITING TWO-ADDR INSTRS **********\n");
- DEBUG(dbgs() << "********** Function: "
+ DEBUG(dbgs() << "********** Function: "
<< MF.getFunction()->getName() << '\n');
// This pass takes the function out of SSA form.
}
}
+// Find the first def of Reg, assuming they are all in the same basic block.
+static MachineInstr *findFirstDef(unsigned Reg, MachineRegisterInfo *MRI) {
+ SmallPtrSet<MachineInstr*, 8> Defs;
+ MachineInstr *First = 0;
+ for (MachineRegisterInfo::def_iterator RI = MRI->def_begin(Reg);
+ MachineInstr *MI = RI.skipInstruction(); Defs.insert(MI))
+ First = MI;
+ if (!First)
+ return 0;
+
+ MachineBasicBlock *MBB = First->getParent();
+ MachineBasicBlock::iterator A = First, B = First;
+ bool Moving;
+ do {
+ Moving = false;
+ if (A != MBB->begin()) {
+ Moving = true;
+ --A;
+ if (Defs.erase(A)) First = A;
+ }
+ if (B != MBB->end()) {
+ Defs.erase(B);
+ ++B;
+ Moving = true;
+ }
+ } while (Moving && !Defs.empty());
+ assert(Defs.empty() && "Instructions outside basic block!");
+ return First;
+}
+
/// CoalesceExtSubRegs - If a number of sources of the REG_SEQUENCE are
/// EXTRACT_SUBREG from the same register and to the same virtual register
/// with different sub-register indices, attempt to combine the
UpdateRegSequenceSrcs(SrcReg, DstReg, SubIdx, MRI, *TRI);
}
+ // Set <def,undef> flags on the first DstReg def in the basic block.
+ // It marks the beginning of the live range. All the other defs are
+ // read-modify-write.
+ if (MachineInstr *Def = findFirstDef(DstReg, MRI)) {
+ for (unsigned i = 0, e = Def->getNumOperands(); i != e; ++i) {
+ MachineOperand &MO = Def->getOperand(i);
+ if (MO.isReg() && MO.isDef() && MO.getReg() == DstReg)
+ MO.setIsUndef();
+ }
+ // Make sure there is a full non-subreg imp-def operand on the
+ // instruction. This shouldn't be necessary, but it seems that at least
+ // RAFast requires it.
+ Def->addRegisterDefined(DstReg, TRI);
+ DEBUG(dbgs() << "First def: " << *Def);
+ }
+
if (IsImpDef) {
DEBUG(dbgs() << "Turned: " << *MI << " into an IMPLICIT_DEF");
MI->setDesc(TII->get(TargetOpcode::IMPLICIT_DEF));
for (int j = MI->getNumOperands() - 1, ee = 0; j > ee; --j)
- MI->RemoveOperand(j);
+ MI->RemoveOperand(j);
} else {
DEBUG(dbgs() << "Eliminated: " << *MI);
MI->eraseFromParent();