After reading memory that's already freed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49810 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SimpleRegisterCoalescing.cpp b/lib/CodeGen/SimpleRegisterCoalescing.cpp
index 15aae58..e9a5e25 100644
--- a/lib/CodeGen/SimpleRegisterCoalescing.cpp
+++ b/lib/CodeGen/SimpleRegisterCoalescing.cpp
@@ -560,8 +560,8 @@
/// removeIntervalIfEmpty - Check if the live interval of a physical register
/// is empty, if so remove it and also remove the empty intervals of its
-/// sub-registers.
-static void removeIntervalIfEmpty(LiveInterval &li, LiveIntervals *li_,
+/// sub-registers. Return true if live interval is removed.
+static bool removeIntervalIfEmpty(LiveInterval &li, LiveIntervals *li_,
const TargetRegisterInfo *tri_) {
if (li.empty()) {
if (TargetRegisterInfo::isPhysicalRegister(li.reg))
@@ -573,25 +573,28 @@
li_->removeInterval(*SR);
}
li_->removeInterval(li.reg);
+ return true;
}
+ return false;
}
/// ShortenDeadCopyLiveRange - Shorten a live range defined by a dead copy.
-///
-void SimpleRegisterCoalescing::ShortenDeadCopyLiveRange(LiveInterval &li,
+/// Return true if live interval is removed.
+bool SimpleRegisterCoalescing::ShortenDeadCopyLiveRange(LiveInterval &li,
MachineInstr *CopyMI) {
unsigned CopyIdx = li_->getInstructionIndex(CopyMI);
LiveInterval::iterator MLR =
li.FindLiveRangeContaining(li_->getDefIndex(CopyIdx));
if (MLR == li.end())
- return; // Already removed by ShortenDeadCopySrcLiveRange.
+ return false; // Already removed by ShortenDeadCopySrcLiveRange.
unsigned RemoveStart = MLR->start;
unsigned RemoveEnd = MLR->end;
// Remove the liverange that's defined by this.
if (RemoveEnd == li_->getDefIndex(CopyIdx)+1) {
removeRange(li, RemoveStart, RemoveEnd, li_, tri_);
- removeIntervalIfEmpty(li, li_, tri_);
+ return removeIntervalIfEmpty(li, li_, tri_);
}
+ return false;
}
/// PropagateDeadness - Propagate the dead marker to the instruction which
@@ -614,8 +617,8 @@
/// ShortenDeadCopyLiveRange - Shorten a live range as it's artificially
/// extended by a dead copy. Mark the last use (if any) of the val# as kill
/// as ends the live range there. If there isn't another use, then this
-/// live range is dead.
-void
+/// live range is dead. Return true if live interval is removed.
+bool
SimpleRegisterCoalescing::ShortenDeadCopySrcLiveRange(LiveInterval &li,
MachineInstr *CopyMI) {
unsigned CopyIdx = li_->getInstructionIndex(CopyMI);
@@ -627,20 +630,19 @@
mf_->begin()->removeLiveIn(li.reg);
const LiveRange *LR = li.getLiveRangeContaining(CopyIdx);
removeRange(li, LR->start, LR->end, li_, tri_);
- removeIntervalIfEmpty(li, li_, tri_);
- return;
+ return removeIntervalIfEmpty(li, li_, tri_);
}
LiveInterval::iterator LR = li.FindLiveRangeContaining(CopyIdx-1);
if (LR == li.end())
// Livein but defined by a phi.
- return;
+ return false;
unsigned RemoveStart = LR->start;
unsigned RemoveEnd = li_->getDefIndex(CopyIdx)+1;
if (LR->end > RemoveEnd)
// More uses past this copy? Nothing to do.
- return;
+ return false;
unsigned LastUseIdx;
MachineOperand *LastUse = lastRegisterUse(LR->start, CopyIdx-1, li.reg,
@@ -658,7 +660,7 @@
int DeadIdx = LastUseMI->findRegisterDefOperandIdx(li.reg, false, tri_);
LastUseMI->getOperand(DeadIdx).setIsDead();
}
- return;
+ return false;
}
// Is it livein?
@@ -678,7 +680,7 @@
PropagateDeadness(li, CopyMI, RemoveStart, li_, tri_);
removeRange(li, RemoveStart, LR->end, li_, tri_);
- removeIntervalIfEmpty(li, li_, tri_);
+ return removeIntervalIfEmpty(li, li_, tri_);
}
/// CanCoalesceWithImpDef - Returns true if the specified copy instruction
@@ -1952,8 +1954,8 @@
}
if (CopyMI->registerDefIsDead(DstReg)) {
LiveInterval &li = li_->getInterval(DstReg);
- ShortenDeadCopySrcLiveRange(li, CopyMI);
- ShortenDeadCopyLiveRange(li, CopyMI);
+ if (!ShortenDeadCopySrcLiveRange(li, CopyMI))
+ ShortenDeadCopyLiveRange(li, CopyMI);
}
li_->RemoveMachineInstrFromMaps(*I);
(*I)->eraseFromParent();
@@ -1979,8 +1981,8 @@
// If def of this move instruction is dead, remove its live range
// from the dstination register's live interval.
if (mii->registerDefIsDead(dstReg)) {
- ShortenDeadCopySrcLiveRange(RegInt, mii);
- ShortenDeadCopyLiveRange(RegInt, mii);
+ if (!ShortenDeadCopySrcLiveRange(RegInt, mii))
+ ShortenDeadCopyLiveRange(RegInt, mii);
}
}
li_->RemoveMachineInstrFromMaps(mii);