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Change VisitedPHIs into an instance variable that's freed by each alias() call. 

llvm-svn: 84072
This commit is contained in:
Evan Cheng 2009-10-14 05:05:02 +00:00
parent 7d6387bb24
commit 31565b3e9f
1 changed files with 22 additions and 22 deletions
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44
llvm/lib/Analysis/BasicAliasAnalysis.cpp
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@ -203,8 +203,8 @@ namespace {
BasicAliasAnalysis() : NoAA(&ID) {}
AliasResult alias(const Value *V1, unsigned V1Size,
const Value *V2, unsigned V2Size) {
SmallSet<const Value*, 16> VisitedPHIs;
return aliasCheck(V1, V1Size, V2, V2Size, VisitedPHIs);
VisitedPHIs.clear();
return aliasCheck(V1, V1Size, V2, V2Size);
}
ModRefResult getModRefInfo(CallSite CS, Value *P, unsigned Size);
@ -219,19 +219,21 @@ namespace {
bool pointsToConstantMemory(const Value *P);
private:
// VisitedPHIs - Track PHI nodes visited by a aliasCheck() call.
SmallSet<const Value*, 16> VisitedPHIs;
// aliasGEP - Provide a bunch of ad-hoc rules to disambiguate a GEP instruction
// against another.
AliasResult aliasGEP(const Value *V1, unsigned V1Size,
const Value *V2, unsigned V2Size,
SmallSet<const Value*, 16> &VisitedPHIs);
const Value *V2, unsigned V2Size);
// aliasGEP - Provide a bunch of ad-hoc rules to disambiguate a PHI instruction
// against another.
AliasResult aliasPHI(const Value *V1, unsigned V1Size,
const Value *V2, unsigned V2Size,
SmallSet<const Value*, 16> &VisitedPHIs);
const Value *V2, unsigned V2Size);
AliasResult aliasCheck(const Value *V1, unsigned V1Size,
const Value *V2, unsigned V2Size,
SmallSet<const Value*, 16> &VisitedPHIs);
const Value *V2, unsigned V2Size);
// CheckGEPInstructions - Check two GEP instructions with known
// must-aliasing base pointers. This checks to see if the index expressions
@ -352,8 +354,7 @@ BasicAliasAnalysis::getModRefInfo(CallSite CS1, CallSite CS2) {
//
AliasAnalysis::AliasResult
BasicAliasAnalysis::aliasGEP(const Value *V1, unsigned V1Size,
const Value *V2, unsigned V2Size,
SmallSet<const Value*, 16> &VisitedPHIs) {
const Value *V2, unsigned V2Size) {
// If we have two gep instructions with must-alias'ing base pointers, figure
// out if the indexes to the GEP tell us anything about the derived pointer.
// Note that we also handle chains of getelementptr instructions as well as
@ -374,7 +375,7 @@ BasicAliasAnalysis::aliasGEP(const Value *V1, unsigned V1Size,
// All operands are the same, ignoring the base.
std::equal(GEP1->op_begin()+1, GEP1->op_end(), GEP2->op_begin()+1))
return aliasCheck(GEP1->getOperand(0), V1Size,
GEP2->getOperand(0), V2Size, VisitedPHIs);
GEP2->getOperand(0), V2Size);
// Drill down into the first non-gep value, to test for must-aliasing of
// the base pointers.
@ -391,8 +392,7 @@ BasicAliasAnalysis::aliasGEP(const Value *V1, unsigned V1Size,
const Value *BasePtr2 = GEP2->getOperand(0);
// Do the base pointers alias?
AliasResult BaseAlias = aliasCheck(BasePtr1, ~0U, BasePtr2, ~0U,
VisitedPHIs);
AliasResult BaseAlias = aliasCheck(BasePtr1, ~0U, BasePtr2, ~0U);
if (BaseAlias == NoAlias) return NoAlias;
if (BaseAlias == MustAlias) {
// If the base pointers alias each other exactly, check to see if we can
@ -428,7 +428,7 @@ BasicAliasAnalysis::aliasGEP(const Value *V1, unsigned V1Size,
SmallVector<Value*, 16> GEPOperands;
const Value *BasePtr = GetGEPOperands(V1, GEPOperands);
AliasResult R = aliasCheck(BasePtr, V1Size, V2, V2Size, VisitedPHIs);
AliasResult R = aliasCheck(BasePtr, V1Size, V2, V2Size);
if (R == MustAlias) {
// If there is at least one non-zero constant index, we know they cannot
// alias.
@ -477,10 +477,11 @@ BasicAliasAnalysis::aliasGEP(const Value *V1, unsigned V1Size,
return MayAlias;
}
// aliasGEP - Provide a bunch of ad-hoc rules to disambiguate a PHI instruction
// against another.
AliasAnalysis::AliasResult
BasicAliasAnalysis::aliasPHI(const Value *V1, unsigned V1Size,
const Value *V2, unsigned V2Size,
SmallSet<const Value*, 16> &VisitedPHIs) {
const Value *V2, unsigned V2Size) {
// The PHI node has already been visited, avoid recursion any further.
if (!VisitedPHIs.insert(V1))
return MayAlias;
@ -500,10 +501,10 @@ BasicAliasAnalysis::aliasPHI(const Value *V1, unsigned V1Size,
// If all sources of the PHI node NoAlias or MustAlias V2, then returns
// NoAlias / MustAlias. Otherwise, returns MayAlias.
AliasResult Alias = aliasCheck(V1Srcs[0], V1Size, V2, V2Size, VisitedPHIs);
AliasResult Alias = aliasCheck(V1Srcs[0], V1Size, V2, V2Size);
for (unsigned i = 1, e = V1Srcs.size(); i != e; ++i) {
Value *V = V1Srcs[i];
AliasResult ThisAlias = aliasCheck(V, V1Size, V2, V2Size, VisitedPHIs);
AliasResult ThisAlias = aliasCheck(V, V1Size, V2, V2Size);
if (ThisAlias != Alias)
return MayAlias;
}
@ -516,8 +517,7 @@ BasicAliasAnalysis::aliasPHI(const Value *V1, unsigned V1Size,
//
AliasAnalysis::AliasResult
BasicAliasAnalysis::aliasCheck(const Value *V1, unsigned V1Size,
const Value *V2, unsigned V2Size,
SmallSet<const Value*, 16> &VisitedPHIs) {
const Value *V2, unsigned V2Size) {
// Strip off any casts if they exist.
V1 = V1->stripPointerCasts();
V2 = V2->stripPointerCasts();
@ -571,14 +571,14 @@ BasicAliasAnalysis::aliasCheck(const Value *V1, unsigned V1Size,
std::swap(V1Size, V2Size);
}
if (isGEP(V1))
return aliasGEP(V1, V1Size, V2, V2Size, VisitedPHIs);
return aliasGEP(V1, V1Size, V2, V2Size);
if (isa<PHINode>(V2) && !isa<PHINode>(V1)) {
std::swap(V1, V2);
std::swap(V1Size, V2Size);
}
if (isa<PHINode>(V1))
return aliasPHI(V1, V1Size, V2, V2Size, VisitedPHIs);
return aliasPHI(V1, V1Size, V2, V2Size);
return MayAlias;
}