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Fix PR2226. Avoid using uninitialized variables.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49807 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2008-04-16 18:48:43 +00:00
parent a5261923b4
commit ff7a3e557e
1 changed files with 28 additions and 13 deletions
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41
lib/CodeGen/SimpleRegisterCoalescing.cpp
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@ -97,6 +97,8 @@ bool SimpleRegisterCoalescing::AdjustCopiesBackFrom(LiveInterval &IntA,
// BValNo is a value number in B that is defined by a copy from A. 'B3' in
// the example above.
LiveInterval::iterator BLR = IntB.FindLiveRangeContaining(CopyIdx);
if (BLR == IntB.end()) // Should never happen!
return false;
VNInfo *BValNo = BLR->valno;
// Get the location that B is defined at. Two options: either this value has
@ -107,6 +109,8 @@ bool SimpleRegisterCoalescing::AdjustCopiesBackFrom(LiveInterval &IntA,
// AValNo is the value number in A that defines the copy, A3 in the example.
LiveInterval::iterator ALR = IntA.FindLiveRangeContaining(CopyIdx-1);
if (ALR == IntA.end()) // Should never happen!
return false;
VNInfo *AValNo = ALR->valno;
// If AValNo is defined as a copy from IntB, we can potentially process this.
@ -122,6 +126,8 @@ bool SimpleRegisterCoalescing::AdjustCopiesBackFrom(LiveInterval &IntA,
// Get the LiveRange in IntB that this value number starts with.
LiveInterval::iterator ValLR = IntB.FindLiveRangeContaining(AValNo->def-1);
if (ValLR == IntB.end()) // Should never happen!
return false;
// Make sure that the end of the live range is inside the same block as
// CopyMI.
@ -251,6 +257,8 @@ bool SimpleRegisterCoalescing::RemoveCopyByCommutingDef(LiveInterval &IntA,
// BValNo is a value number in B that is defined by a copy from A. 'B3' in
// the example above.
LiveInterval::iterator BLR = IntB.FindLiveRangeContaining(CopyIdx);
if (BLR == IntB.end()) // Should never happen!
return false;
VNInfo *BValNo = BLR->valno;
// Get the location that B is defined at. Two options: either this value has
@ -261,6 +269,8 @@ bool SimpleRegisterCoalescing::RemoveCopyByCommutingDef(LiveInterval &IntA,
// AValNo is the value number in A that defines the copy, A3 in the example.
LiveInterval::iterator ALR = IntA.FindLiveRangeContaining(CopyIdx-1);
if (ALR == IntA.end()) // Should never happen!
return false;
VNInfo *AValNo = ALR->valno;
// If other defs can reach uses of this def, then it's not safe to perform
// the optimization.
@ -290,6 +300,8 @@ bool SimpleRegisterCoalescing::RemoveCopyByCommutingDef(LiveInterval &IntA,
MachineInstr *UseMI = &*UI;
unsigned UseIdx = li_->getInstructionIndex(UseMI);
LiveInterval::iterator ULR = IntA.FindLiveRangeContaining(UseIdx);
if (ULR == IntA.end())
continue;
if (ULR->valno == AValNo && JoinedCopies.count(UseMI))
return false;
}
@ -337,7 +349,7 @@ bool SimpleRegisterCoalescing::RemoveCopyByCommutingDef(LiveInterval &IntA,
continue;
unsigned UseIdx = li_->getInstructionIndex(UseMI);
LiveInterval::iterator ULR = IntA.FindLiveRangeContaining(UseIdx);
if (ULR->valno != AValNo)
if (ULR == IntA.end() || ULR->valno != AValNo)
continue;
UseMO.setReg(NewReg);
if (UseMI == CopyMI)
@ -356,7 +368,7 @@ bool SimpleRegisterCoalescing::RemoveCopyByCommutingDef(LiveInterval &IntA,
// remove that val# as well. However this live range is being
// extended to the end of the existing live range defined by the copy.
unsigned DefIdx = li_->getDefIndex(UseIdx);
LiveInterval::iterator DLR = IntB.FindLiveRangeContaining(DefIdx);
const LiveRange *DLR = IntB.getLiveRangeContaining(DefIdx);
BHasPHIKill |= DLR->valno->hasPHIKill;
assert(DLR->valno->def == DefIdx);
BDeadValNos.push_back(DLR->valno);
@ -515,8 +527,7 @@ void SimpleRegisterCoalescing::RemoveUnnecessaryKills(unsigned Reg,
unsigned UseIdx = li_->getUseIndex(li_->getInstructionIndex(UseMI));
if (JoinedCopies.count(UseMI))
continue;
LiveInterval::const_iterator UI = LI.FindLiveRangeContaining(UseIdx);
assert(UI != LI.end());
const LiveRange *UI = LI.getLiveRangeContaining(UseIdx);
if (!LI.isKill(UI->valno, UseIdx+1))
UseMO.setIsKill(false);
}
@ -614,7 +625,7 @@ SimpleRegisterCoalescing::ShortenDeadCopySrcLiveRange(LiveInterval &li,
assert(TargetRegisterInfo::isPhysicalRegister(li.reg));
// Live-in to the function but dead. Remove it from entry live-in set.
mf_->begin()->removeLiveIn(li.reg);
LiveInterval::iterator LR = li.FindLiveRangeContaining(CopyIdx);
const LiveRange *LR = li.getLiveRangeContaining(CopyIdx);
removeRange(li, LR->start, LR->end, li_, tri_);
removeIntervalIfEmpty(li, li_, tri_);
return;
@ -694,7 +705,7 @@ bool SimpleRegisterCoalescing::CanCoalesceWithImpDef(MachineInstr *CopyMI,
continue;
unsigned UseIdx = li_->getUseIndex(li_->getInstructionIndex(UseMI));
LiveInterval::iterator ULR = li.FindLiveRangeContaining(UseIdx);
if (ULR->valno != LR->valno)
if (ULR == li.end() || ULR->valno != LR->valno)
continue;
// If the use is not a use, then it's not safe to coalesce the move.
unsigned SrcReg, DstReg;
@ -733,7 +744,7 @@ void SimpleRegisterCoalescing::RemoveCopiesFromValNo(LiveInterval &li,
continue;
unsigned UseIdx = li_->getUseIndex(li_->getInstructionIndex(MI));
LiveInterval::iterator ULR = li.FindLiveRangeContaining(UseIdx);
if (ULR->valno != VNI)
if (ULR == li.end() || ULR->valno != VNI)
continue;
// If the use is a copy, turn it into an identity copy.
unsigned SrcReg, DstReg;
@ -1013,9 +1024,8 @@ bool SimpleRegisterCoalescing::JoinCopy(CopyRec &TheCopy, bool &Again) {
SmallSet<const VNInfo*, 4> CopiedValNos;
for (LiveInterval::Ranges::const_iterator I = ResSrcInt->ranges.begin(),
E = ResSrcInt->ranges.end(); I != E; ++I) {
LiveInterval::const_iterator DstLR =
ResDstInt->FindLiveRangeContaining(I->start);
assert(DstLR != ResDstInt->end() && "Invalid joined interval!");
const LiveRange *DstLR = ResDstInt->getLiveRangeContaining(I->start);
assert(DstLR && "Invalid joined interval!");
const VNInfo *DstValNo = DstLR->valno;
if (CopiedValNos.insert(DstValNo)) {
VNInfo *ValNo = RealInt.getNextValue(DstValNo->def, DstValNo->copy,
@ -1095,7 +1105,7 @@ bool SimpleRegisterCoalescing::JoinCopy(CopyRec &TheCopy, bool &Again) {
// by the copy is being defined by an IMPLICIT_DEF which defines a zero
// length interval. Remove the val#.
unsigned CopyIdx = li_->getDefIndex(li_->getInstructionIndex(CopyMI));
LiveInterval::iterator LR = ResDstInt->FindLiveRangeContaining(CopyIdx);
const LiveRange *LR = ResDstInt->getLiveRangeContaining(CopyIdx);
VNInfo *ImpVal = LR->valno;
assert(ImpVal->def == CopyIdx);
unsigned NextDef = LR->end;
@ -1877,7 +1887,7 @@ SimpleRegisterCoalescing::TurnCopyIntoImpDef(MachineBasicBlock::iterator &I,
if (!li_->hasInterval(DstReg))
return false;
LiveInterval &DstInt = li_->getInterval(DstReg);
LiveInterval::iterator DstLR = DstInt.FindLiveRangeContaining(CopyIdx);
const LiveRange *DstLR = DstInt.getLiveRangeContaining(CopyIdx);
DstInt.removeValNo(DstLR->valno);
CopyMI->setDesc(tii_->get(TargetInstrInfo::IMPLICIT_DEF));
for (int i = CopyMI->getNumOperands() - 1, e = 0; i > e; --i)
@ -1934,7 +1944,12 @@ bool SimpleRegisterCoalescing::runOnMachineFunction(MachineFunction &fn) {
E = JoinedCopies.end(); I != E; ++I) {
MachineInstr *CopyMI = *I;
unsigned SrcReg, DstReg;
tii_->isMoveInstr(*CopyMI, SrcReg, DstReg);
if (!tii_->isMoveInstr(*CopyMI, SrcReg, DstReg)) {
assert((CopyMI->getOpcode() == TargetInstrInfo::EXTRACT_SUBREG ||
CopyMI->getOpcode() == TargetInstrInfo::INSERT_SUBREG) &&
"Unrecognized copy instruction");
DstReg = CopyMI->getOperand(0).getReg();
}
if (CopyMI->registerDefIsDead(DstReg)) {
LiveInterval &li = li_->getInterval(DstReg);
ShortenDeadCopySrcLiveRange(li, CopyMI);