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Refactor some code into separate functions. No functional changes.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80733 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bob Wilson 2009-09-01 22:51:08 +00:00
parent c08f5fe882
commit 326f43812c
1 changed files with 82 additions and 52 deletions
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134
lib/CodeGen/TwoAddressInstructionPass.cpp
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@ -106,6 +106,15 @@ namespace {
MachineFunction::iterator &mbbi,
unsigned RegB, unsigned Dist);
typedef std::pair<std::pair<unsigned, bool>, MachineInstr*> NewKill;
bool canUpdateDeletedKills(SmallVector<unsigned, 4> &Kills,
SmallVector<NewKill, 4> &NewKills,
MachineBasicBlock *MBB, unsigned Dist);
bool DeleteUnusedInstr(MachineBasicBlock::iterator &mi,
MachineBasicBlock::iterator &nmi,
MachineFunction::iterator &mbbi,
unsigned regB, unsigned regBIdx, unsigned Dist);
void ProcessCopy(MachineInstr *MI, MachineBasicBlock *MBB,
SmallPtrSet<MachineInstr*, 8> &Processed);
@ -736,6 +745,75 @@ static bool isSafeToDelete(MachineInstr *MI, unsigned Reg,
return true;
}
/// canUpdateDeletedKills - Check if all the registers listed in Kills are
/// killed by instructions in MBB preceding the current instruction at
/// position Dist. If so, return true and record information about the
/// preceding kills in NewKills.
bool TwoAddressInstructionPass::
canUpdateDeletedKills(SmallVector<unsigned, 4> &Kills,
SmallVector<NewKill, 4> &NewKills,
MachineBasicBlock *MBB, unsigned Dist) {
while (!Kills.empty()) {
unsigned Kill = Kills.back();
Kills.pop_back();
if (TargetRegisterInfo::isPhysicalRegister(Kill))
return false;
MachineInstr *LastKill = FindLastUseInMBB(Kill, MBB, Dist);
if (!LastKill)
return false;
bool isModRef = LastKill->modifiesRegister(Kill);
NewKills.push_back(std::make_pair(std::make_pair(Kill, isModRef),
LastKill));
}
return true;
}
/// DeleteUnusedInstr - If an instruction with a tied register operand can
/// be safely deleted, just delete it.
bool
TwoAddressInstructionPass::DeleteUnusedInstr(MachineBasicBlock::iterator &mi,
MachineBasicBlock::iterator &nmi,
MachineFunction::iterator &mbbi,
unsigned regB, unsigned regBIdx,
unsigned Dist) {
// Check if the instruction has no side effects and if all its defs are dead.
SmallVector<unsigned, 4> Kills;
if (!isSafeToDelete(mi, regB, TII, Kills))
return false;
// If this instruction kills some virtual registers, we need to
// update the kill information. If it's not possible to do so,
// then bail out.
SmallVector<NewKill, 4> NewKills;
if (!canUpdateDeletedKills(Kills, NewKills, &*mbbi, Dist))
return false;
if (LV) {
while (!NewKills.empty()) {
MachineInstr *NewKill = NewKills.back().second;
unsigned Kill = NewKills.back().first.first;
bool isDead = NewKills.back().first.second;
NewKills.pop_back();
if (LV->removeVirtualRegisterKilled(Kill, mi)) {
if (isDead)
LV->addVirtualRegisterDead(Kill, NewKill);
else
LV->addVirtualRegisterKilled(Kill, NewKill);
}
}
// If regB was marked as a kill, update its Kills list.
if (mi->getOperand(regBIdx).isKill())
LV->removeVirtualRegisterKilled(regB, mi);
}
mbbi->erase(mi); // Nuke the old inst.
mi = nmi;
return true;
}
/// runOnMachineFunction - Reduce two-address instructions to two operands.
///
bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) {
@ -822,61 +900,13 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) {
// allow us to coalesce A and B together, eliminating the copy we are
// about to insert.
if (!isKilled(*mi, regB, MRI, TII)) {
// If regA is dead and the instruction can be deleted, just delete
// it so it doesn't clobber regB.
SmallVector<unsigned, 4> Kills;
if (mi->getOperand(ti).isDead() &&
isSafeToDelete(mi, regB, TII, Kills)) {
SmallVector<std::pair<std::pair<unsigned, bool>
,MachineInstr*>, 4> NewKills;
bool ReallySafe = true;
// If this instruction kills some virtual registers, we need
// update the kill information. If it's not possible to do so,
// then bail out.
while (!Kills.empty()) {
unsigned Kill = Kills.back();
Kills.pop_back();
if (TargetRegisterInfo::isPhysicalRegister(Kill)) {
ReallySafe = false;
break;
}
MachineInstr *LastKill = FindLastUseInMBB(Kill, &*mbbi, Dist);
if (LastKill) {
bool isModRef = LastKill->modifiesRegister(Kill);
NewKills.push_back(std::make_pair(std::make_pair(Kill,isModRef),
LastKill));
} else {
ReallySafe = false;
break;
}
}
if (ReallySafe) {
if (LV) {
while (!NewKills.empty()) {
MachineInstr *NewKill = NewKills.back().second;
unsigned Kill = NewKills.back().first.first;
bool isDead = NewKills.back().first.second;
NewKills.pop_back();
if (LV->removeVirtualRegisterKilled(Kill, mi)) {
if (isDead)
LV->addVirtualRegisterDead(Kill, NewKill);
else
LV->addVirtualRegisterKilled(Kill, NewKill);
}
}
// We're really going to nuke the old inst. If regB was marked
// as a kill we need to update its Kills list.
if (mi->getOperand(si).isKill())
LV->removeVirtualRegisterKilled(regB, mi);
}
mbbi->erase(mi); // Nuke the old inst.
mi = nmi;
++NumDeletes;
break; // Done with this instruction.
}
DeleteUnusedInstr(mi, nmi, mbbi, regB, si, Dist)) {
++NumDeletes;
break; // Done with this instruction.
}
// If this instruction is commutative, check to see if C dies. If