diff options
Diffstat (limited to 'llvm/lib/Analysis')
| -rw-r--r-- | llvm/lib/Analysis/BasicAliasAnalysis.cpp | 44 |
1 files changed, 22 insertions, 22 deletions
diff --git a/llvm/lib/Analysis/BasicAliasAnalysis.cpp b/llvm/lib/Analysis/BasicAliasAnalysis.cpp index 75fd0e8f228..8a2282a4693 100644 --- a/llvm/lib/Analysis/BasicAliasAnalysis.cpp +++ b/llvm/lib/Analysis/BasicAliasAnalysis.cpp @@ -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; } |
