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Add initial support for inserting last minute copies.

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llvm-svn: 56485
This commit is contained in:
Owen Anderson 2008-09-23 04:37:10 +00:00
parent 5bf702d20a
commit 5405b59bcd
1 changed files with 53 additions and 28 deletions
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81
lib/CodeGen/StrongPHIElimination.cpp
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@ -142,7 +142,7 @@ namespace {
void ScheduleCopies(MachineBasicBlock* MBB, std::set<unsigned>& pushed);
void InsertCopies(MachineDomTreeNode* MBB,
SmallPtrSet<MachineBasicBlock*, 16>& v);
void mergeLiveIntervals(unsigned primary, unsigned secondary);
bool mergeLiveIntervals(unsigned primary, unsigned secondary);
};
}
@ -844,7 +844,7 @@ void StrongPHIElimination::InsertCopies(MachineDomTreeNode* MDTN,
Stacks[*I].pop_back();
}
void StrongPHIElimination::mergeLiveIntervals(unsigned primary,
bool StrongPHIElimination::mergeLiveIntervals(unsigned primary,
unsigned secondary) {
LiveIntervals& LI = getAnalysis<LiveIntervals>();
@ -859,32 +859,35 @@ void StrongPHIElimination::mergeLiveIntervals(unsigned primary,
unsigned Start = R.start;
unsigned End = R.end;
if (LHS.liveAt(Start))
LHS.removeRange(Start, End, true);
if (LHS.getLiveRangeContaining(Start))
return false;
if (const LiveRange* ER = LHS.getLiveRangeContaining(End))
End = ER->start;
if (LHS.getLiveRangeContaining(End))
return false;
LiveInterval::iterator RI = std::upper_bound(LHS.begin(), LHS.end(), R);
if (RI != LHS.end() && RI->start < End)
End = RI->start;
if (Start != End) {
VNInfo* OldVN = R.valno;
VNInfo*& NewVN = VNMap[OldVN];
if (!NewVN) {
NewVN = LHS.getNextValue(OldVN->def,
OldVN->copy,
LI.getVNInfoAllocator());
NewVN->kills = OldVN->kills;
}
LiveRange LR (Start, End, NewVN);
LHS.addRange(LR);
return false;
}
for (LiveInterval::iterator I = RHS.begin(), E = RHS.end(); I != E; ++I) {
LiveRange R = *I;
VNInfo* OldVN = R.valno;
VNInfo*& NewVN = VNMap[OldVN];
if (!NewVN) {
NewVN = LHS.getNextValue(OldVN->def,
OldVN->copy,
LI.getVNInfoAllocator());
NewVN->kills = OldVN->kills;
}
LiveRange LR (R.start, R.end, NewVN);
LHS.addRange(LR);
}
LI.removeInterval(RHS.reg);
return true;
}
bool StrongPHIElimination::runOnMachineFunction(MachineFunction &Fn) {
@ -936,21 +939,43 @@ bool StrongPHIElimination::runOnMachineFunction(MachineFunction &Fn) {
DOUT << "Renaming: " << SI->first << " -> " << I->first << "\n";
if (SI->first != I->first) {
mergeLiveIntervals(I->first, SI->first);
Fn.getRegInfo().replaceRegWith(SI->first, I->first);
if (mergeLiveIntervals(I->first, SI->first)) {
Fn.getRegInfo().replaceRegWith(SI->first, I->first);
if (RenameSets.count(SI->first)) {
I->second.insert(RenameSets[SI->first].begin(),
RenameSets[SI->first].end());
RenameSets.erase(SI->first);
if (RenameSets.count(SI->first)) {
I->second.insert(RenameSets[SI->first].begin(),
RenameSets[SI->first].end());
RenameSets.erase(SI->first);
}
} else {
// Insert a last-minute copy if a conflict was detected.
const TargetInstrInfo *TII = Fn.getTarget().getInstrInfo();
const TargetRegisterClass *RC = Fn.getRegInfo().getRegClass(I->first);
TII->copyRegToReg(*SI->second, SI->second->getFirstTerminator(),
I->first, SI->first, RC, RC);
LI.computeNumbering();
LiveInterval& Int = LI.getOrCreateInterval(I->first);
unsigned instrIdx =
LI.getInstructionIndex(--SI->second->getFirstTerminator());
if (Int.liveAt(LiveIntervals::getDefIndex(instrIdx)))
Int.removeRange(LiveIntervals::getDefIndex(instrIdx),
LI.getMBBEndIdx(SI->second)+1, true);
LiveRange R = LI.addLiveRangeToEndOfBlock(I->first,
--SI->second->getFirstTerminator());
R.valno->copy = --SI->second->getFirstTerminator();
R.valno->def = LiveIntervals::getDefIndex(instrIdx);
DOUT << "Renaming failed: " << SI->first << " -> "
<< I->first << "\n";
}
}
I->second.erase(SI->first);
}
// FIXME: Insert last-minute copies
// Remove PHIs
std::vector<MachineInstr*> phis;
for (MachineFunction::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I) {