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Use of implicit_def is not part of live interval. Create empty intervals for the uses when the live interval is being spilled.

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llvm-svn: 49542
This commit is contained in:
Evan Cheng
2008-04-11 17:53:36 +00:00
parent bde1bbed16
commit 499ffa9055
4 changed files with 58 additions and 15 deletions
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42
llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
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@@ -1319,19 +1319,37 @@ void LiveIntervals::eraseRestoreInfo(int Id, int index, unsigned vr,
Restores[i].index = -1;
}
/// removeSpilledImpDefs - Remove IMPLICIT_DEF instructions which are being
/// spilled.
void LiveIntervals::removeSpilledImpDefs(const LiveInterval &li,
VirtRegMap &vrm) {
/// handleSpilledImpDefs - Remove IMPLICIT_DEF instructions which are being
/// spilled and create empty intervals for their uses.
void
LiveIntervals::handleSpilledImpDefs(const LiveInterval &li, VirtRegMap &vrm,
const TargetRegisterClass* rc,
std::vector<LiveInterval*> &NewLIs) {
for (MachineRegisterInfo::reg_iterator ri = mri_->reg_begin(li.reg),
re = mri_->reg_end(); ri != re; ) {
MachineOperand &O = ri.getOperand();
MachineInstr *MI = &*ri;
++ri;
if (MI->getOpcode() != TargetInstrInfo::IMPLICIT_DEF)
continue;
RemoveMachineInstrFromMaps(MI);
vrm.RemoveMachineInstrFromMaps(MI);
MI->eraseFromParent();
if (O.isDef()) {
assert(MI->getOpcode() == TargetInstrInfo::IMPLICIT_DEF &&
"Register def was not rewritten?");
RemoveMachineInstrFromMaps(MI);
vrm.RemoveMachineInstrFromMaps(MI);
MI->eraseFromParent();
} else {
// This must be an use of an implicit_def so it's not part of the live
// interval. Create a new empty live interval for it.
// FIXME: Can we simply erase some of the instructions? e.g. Stores?
unsigned NewVReg = mri_->createVirtualRegister(rc);
vrm.grow();
vrm.setIsImplicitlyDefined(NewVReg);
NewLIs.push_back(&getOrCreateInterval(NewVReg));
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
MachineOperand &MO = MI->getOperand(i);
if (MO.isReg() && MO.getReg() == li.reg)
MO.setReg(NewVReg);
}
}
}
}
@@ -1415,7 +1433,7 @@ addIntervalsForSpills(const LiveInterval &li,
IsFirstRange = false;
}
removeSpilledImpDefs(li, vrm);
handleSpilledImpDefs(li, vrm, rc, NewLIs);
return NewLIs;
}
@@ -1485,7 +1503,7 @@ addIntervalsForSpills(const LiveInterval &li,
// Insert spills / restores if we are splitting.
if (!TrySplit) {
removeSpilledImpDefs(li, vrm);
handleSpilledImpDefs(li, vrm, rc, NewLIs);
return NewLIs;
}
@@ -1640,7 +1658,7 @@ addIntervalsForSpills(const LiveInterval &li,
}
}
removeSpilledImpDefs(li, vrm);
handleSpilledImpDefs(li, vrm, rc, RetNewLIs);
return RetNewLIs;
}