I think this was already the intention, but DeadMachineInstructionElim
was accidentally tracking the liveness of reserved registers. Now,
instructions with reserved defs are never deleted.
This prevents the call stack adjustment instructions from getting
deleted when enabling register masks.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150116
91177308-0d34-0410-b5e6-
96231b3b80d8
const MachineRegisterInfo *MRI;
const TargetInstrInfo *TII;
BitVector LivePhysRegs;
const MachineRegisterInfo *MRI;
const TargetInstrInfo *TII;
BitVector LivePhysRegs;
+ BitVector ReservedRegs;
public:
static char ID; // Pass identification, replacement for typeid
public:
static char ID; // Pass identification, replacement for typeid
const MachineOperand &MO = MI->getOperand(i);
if (MO.isReg() && MO.isDef()) {
unsigned Reg = MO.getReg();
const MachineOperand &MO = MI->getOperand(i);
if (MO.isReg() && MO.isDef()) {
unsigned Reg = MO.getReg();
- if (TargetRegisterInfo::isPhysicalRegister(Reg) ?
- LivePhysRegs[Reg] : !MRI->use_nodbg_empty(Reg)) {
- // This def has a non-debug use. Don't delete the instruction!
- return false;
+ if (TargetRegisterInfo::isPhysicalRegister(Reg)) {
+ // Don't delete live physreg defs, or any reserved register defs.
+ if (LivePhysRegs.test(Reg) || ReservedRegs.test(Reg))
+ return false;
+ } else {
+ if (!MRI->use_nodbg_empty(Reg))
+ // This def has a non-debug use. Don't delete the instruction!
+ return false;
TII = MF.getTarget().getInstrInfo();
// Treat reserved registers as always live.
TII = MF.getTarget().getInstrInfo();
// Treat reserved registers as always live.
- BitVector ReservedRegs = TRI->getReservedRegs(MF);
+ ReservedRegs = TRI->getReservedRegs(MF);
// Loop over all instructions in all blocks, from bottom to top, so that it's
// more likely that chains of dependent but ultimately dead instructions will
// Loop over all instructions in all blocks, from bottom to top, so that it's
// more likely that chains of dependent but ultimately dead instructions will
} else if (MO.isRegMask()) {
// Register mask of preserved registers. All clobbers are dead.
LivePhysRegs.clearBitsNotInMask(MO.getRegMask());
} else if (MO.isRegMask()) {
// Register mask of preserved registers. All clobbers are dead.
LivePhysRegs.clearBitsNotInMask(MO.getRegMask());
- LivePhysRegs |= ReservedRegs;
}
}
// Record the physreg uses, after the defs, in case a physreg is
}
}
// Record the physreg uses, after the defs, in case a physreg is