[llvm-commits] [llvm] r49810 - in /llvm/trunk: lib/CodeGen/SimpleRegisterCoalescing.cpp lib/CodeGen/SimpleRegisterCoalescing.h test/CodeGen/PowerPC/2008-04-16-CoalescerBug.ll
Evan Cheng
evan.cheng at apple.com
Wed Apr 16 13:24:26 PDT 2008
Author: evancheng
Date: Wed Apr 16 15:24:25 2008
New Revision: 49810
URL: http://llvm.org/viewvc/llvm-project?rev=49810&view=rev
Log:
After reading memory that's already freed.
Added:
llvm/trunk/test/CodeGen/PowerPC/2008-04-16-CoalescerBug.ll
Modified:
llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp
llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.h
Modified: llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp?rev=49810&r1=49809&r2=49810&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp (original)
+++ llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp Wed Apr 16 15:24:25 2008
@@ -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);
Modified: llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.h?rev=49810&r1=49809&r2=49810&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.h (original)
+++ llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.h Wed Apr 16 15:24:25 2008
@@ -232,14 +232,14 @@
void RemoveUnnecessaryKills(unsigned Reg, LiveInterval &LI);
/// ShortenDeadCopyLiveRange - Shorten a live range defined by a dead copy.
- ///
- void ShortenDeadCopyLiveRange(LiveInterval &li, MachineInstr *CopyMI);
+ /// Return true if live interval is removed.
+ bool ShortenDeadCopyLiveRange(LiveInterval &li, MachineInstr *CopyMI);
/// 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 ShortenDeadCopySrcLiveRange(LiveInterval &li, MachineInstr *CopyMI);
+ /// live range is dead. Return true if live interval is removed.
+ bool ShortenDeadCopySrcLiveRange(LiveInterval &li, MachineInstr *CopyMI);
/// lastRegisterUse - Returns the last use of the specific register between
/// cycles Start and End or NULL if there are no uses.
Added: llvm/trunk/test/CodeGen/PowerPC/2008-04-16-CoalescerBug.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/PowerPC/2008-04-16-CoalescerBug.ll?rev=49810&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/PowerPC/2008-04-16-CoalescerBug.ll (added)
+++ llvm/trunk/test/CodeGen/PowerPC/2008-04-16-CoalescerBug.ll Wed Apr 16 15:24:25 2008
@@ -0,0 +1,14 @@
+; RUN: llvm-as < %s | llc -mtriple=powerpc-apple-darwin
+; Avoid reading memory that's already freed.
+
+ at llvm.used = appending global [1 x i8*] [ i8* bitcast (i32 (i64)* @_Z13GetSectorSizey to i8*) ], section "llvm.metadata" ; <[1 x i8*]*> [#uses=0]
+
+define i32 @_Z13GetSectorSizey(i64 %Base) nounwind {
+entry:
+ br i1 false, label %bb, label %UnifiedReturnBlock
+bb: ; preds = %entry
+ %tmp10 = and i64 0, %Base ; <i64> [#uses=0]
+ ret i32 0
+UnifiedReturnBlock: ; preds = %entry
+ ret i32 131072
+}
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