MBBI = MBB->begin();
Tracking = true;
} else {
- assert(MBBI != MBB->end() && "Already at the end of the basic block!");
+ assert(MBBI != MBB->end() && "Already past the end of the basic block!");
MBBI = llvm::next(MBBI);
}
+ assert(MBBI != MBB->end() && "Already at the end of the basic block!");
MachineInstr *MI = MBBI;
BitVector DeadRegs(NumPhysRegs);
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
const MachineOperand &MO = MI->getOperand(i);
- if (!MO.isReg() || MO.isUndef())
+ if (!MO.isReg())
continue;
unsigned Reg = MO.getReg();
if (!Reg || isReserved(Reg))
continue;
if (MO.isUse()) {
+ // Ignore undef uses.
+ if (MO.isUndef())
+ continue;
// Two-address operands implicitly kill.
if (!isPred && (MO.isKill() || MI->isRegTiedToDefOperand(i)))
addRegWithSubRegs(KillRegs, Reg);
// Verify uses and defs.
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
const MachineOperand &MO = MI->getOperand(i);
- if (!MO.isReg() || MO.isUndef())
+ if (!MO.isReg())
continue;
unsigned Reg = MO.getReg();
if (!Reg || isReserved(Reg))
continue;
if (MO.isUse()) {
+ if (MO.isUndef())
+ continue;
if (!isUsed(Reg)) {
// Check if it's partial live: e.g.
// D0 = insert_subreg D0<undef>, S0
break;
}
assert(SubUsed && "Using an undefined register!");
+ (void)SubUsed;
}
assert((!EarlyClobberRegs.test(Reg) || MI->isRegTiedToDefOperand(i)) &&
"Using an early clobbered register!");
/// getRegsAvailable - Return all available registers in the register class
/// in Mask.
-void RegScavenger::getRegsAvailable(const TargetRegisterClass *RC,
- BitVector &Mask) {
+BitVector RegScavenger::getRegsAvailable(const TargetRegisterClass *RC) {
+ BitVector Mask(TRI->getNumRegs());
for (TargetRegisterClass::iterator I = RC->begin(), E = RC->end();
I != E; ++I)
if (!isAliasUsed(*I))
Mask.set(*I);
+ return Mask;
}
/// findSurvivorReg - Return the candidate register that is unused for the
}
// Try to find a register that's unused if there is one, as then we won't
- // have to spill.
- if ((Candidates & RegsAvailable).any())
- Candidates &= RegsAvailable;
+ // have to spill. Search explicitly rather than masking out based on
+ // RegsAvailable, as RegsAvailable does not take aliases into account.
+ // That's what getRegsAvailable() is for.
+ BitVector Available = getRegsAvailable(RC);
+
+ if ((Candidates & Available).any())
+ Candidates &= Available;
// Find the register whose use is furthest away.
MachineBasicBlock::iterator UseMI;