Convert INSERT_SUBREG to COPY in TwoAddressInstructionPass.

INSERT_SUBREG will now only appear in SSA machine instructions.

Fix the handling of partial redefs in ProcessImplicitDefs. This is now relevant
since partial redef COPY instructions appear.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107726 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen 2010-07-06 23:26:25 +00:00
parent fca3a25fed
commit ed2185e171
3 changed files with 35 additions and 2 deletions

View File

@ -265,7 +265,7 @@ bool MultipleDefsBySameMI(const MachineInstr &MI, unsigned MOIdx) {
if (MO.getReg() == Reg && MO.isDef()) {
assert(MI.getOperand(MOIdx).getSubReg() != MO.getSubReg() &&
MI.getOperand(MOIdx).getSubReg() &&
MO.getSubReg());
(MO.getSubReg() || MO.isImplicit()));
return true;
}
}

View File

@ -117,10 +117,24 @@ bool ProcessImplicitDefs::runOnMachineFunction(MachineFunction &fn) {
}
}
// Eliminate %reg1032:sub<def> = COPY undef.
if (MI->isCopy() && MI->getOperand(0).getSubReg()) {
MachineOperand &MO = MI->getOperand(1);
if (ImpDefRegs.count(MO.getReg())) {
if (MO.isKill()) {
LiveVariables::VarInfo& vi = lv_->getVarInfo(MO.getReg());
vi.removeKill(MI);
}
MI->eraseFromParent();
Changed = true;
continue;
}
}
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)
@ -145,6 +159,12 @@ bool ProcessImplicitDefs::runOnMachineFunction(MachineFunction &fn) {
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) {

View File

@ -1218,6 +1218,19 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) {
DEBUG(dbgs() << "\t\trewrite to:\t" << *mi);
}
// Rewrite INSERT_SUBREG as COPY now that we no longer need SSA form.
if (mi->isInsertSubreg()) {
// From %reg = INSERT_SUBREG %reg, %subreg, subidx
// To %reg:subidx = COPY %subreg
unsigned SubIdx = mi->getOperand(3).getImm();
mi->RemoveOperand(3);
assert(mi->getOperand(0).getSubReg() == 0 && "Unexpected subreg idx");
mi->getOperand(0).setSubReg(SubIdx);
mi->RemoveOperand(1);
mi->setDesc(TII->get(TargetOpcode::COPY));
DEBUG(dbgs() << "\t\tconvert to:\t" << *mi);
}
// Clear TiedOperands here instead of at the top of the loop
// since most instructions do not have tied operands.
TiedOperands.clear();