When checking whether the special handling for an addrec increment which

[oota-llvm.git] / lib / Analysis / ScalarEvolutionAliasAnalysis.cpp

diff --git a/lib/Analysis/ScalarEvolutionAliasAnalysis.cpp b/lib/Analysis/ScalarEvolutionAliasAnalysis.cpp
index 204d193625ac63a3fe36148ae442c9f524339939..17b254fca60237dff3d3bb7ef42aa38e9cc78ff6 100644 (file)
--- a/lib/Analysis/ScalarEvolutionAliasAnalysis.cpp
+++ b/lib/Analysis/ScalarEvolutionAliasAnalysis.cpp
@@ -10,6 +10,10 @@
 // This file defines the ScalarEvolutionAliasAnalysis pass, which implements a
 // simple alias analysis implemented in terms of ScalarEvolution queries.
 //
+// This differs from traditional loop dependence analysis in that it tests
+// for dependencies within a single iteration of a loop, rather than
+// dependences between different iterations.
+//
 // ScalarEvolution has a more complete understanding of pointer arithmetic
 // than BasicAliasAnalysis' collection of ad-hoc analyses.
 //
@@ -19,7 +23,6 @@
 #include "llvm/Analysis/ScalarEvolutionExpressions.h"
 #include "llvm/Analysis/Passes.h"
 #include "llvm/Pass.h"
-#include "llvm/Support/Compiler.h"
 using namespace llvm;
 
 namespace {
@@ -33,13 +36,23 @@ namespace {
     static char ID; // Class identification, replacement for typeinfo
     ScalarEvolutionAliasAnalysis() : FunctionPass(&ID), SE(0) {}
 
+    /// getAdjustedAnalysisPointer - This method is used when a pass implements
+    /// an analysis interface through multiple inheritance.  If needed, it
+    /// should override this to adjust the this pointer as needed for the
+    /// specified pass info.
+    virtual void *getAdjustedAnalysisPointer(const PassInfo *PI) {
+      if (PI->isPassID(&AliasAnalysis::ID))
+        return (AliasAnalysis*)this;
+      return this;
+    }
+
   private:
     virtual void getAnalysisUsage(AnalysisUsage &AU) const;
     virtual bool runOnFunction(Function &F);
     virtual AliasResult alias(const Value *V1, unsigned V1Size,
                               const Value *V2, unsigned V2Size);
 
-    Value *GetUnderlyingIdentifiedObject(const SCEV *S);
+    Value *GetBaseValue(const SCEV *S);
   };
 }  // End of anonymous namespace
 
@@ -69,25 +82,22 @@ ScalarEvolutionAliasAnalysis::runOnFunction(Function &F) {
   return false;
 }
 
-/// GetUnderlyingIdentifiedObject - Given an expression, try to find an
-/// "identified object" (see AliasAnalysis::isIdentifiedObject) base
-/// value. Return null is none was found.
+/// GetBaseValue - Given an expression, try to find a
+/// base value. Return null is none was found.
 Value *
-ScalarEvolutionAliasAnalysis::GetUnderlyingIdentifiedObject(const SCEV *S) {
+ScalarEvolutionAliasAnalysis::GetBaseValue(const SCEV *S) {
   if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) {
     // In an addrec, assume that the base will be in the start, rather
     // than the step.
-    return GetUnderlyingIdentifiedObject(AR->getStart());
+    return GetBaseValue(AR->getStart());
   } else if (const SCEVAddExpr *A = dyn_cast<SCEVAddExpr>(S)) {
     // If there's a pointer operand, it'll be sorted at the end of the list.
     const SCEV *Last = A->getOperand(A->getNumOperands()-1);
-    if (isa<PointerType>(Last->getType()))
-      return GetUnderlyingIdentifiedObject(Last);
+    if (Last->getType()->isPointerTy())
+      return GetBaseValue(Last);
   } else if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) {
-    // Determine if we've found an Identified object.
-    Value *V = U->getValue();
-    if (isIdentifiedObject(V))
-      return V;
+    // This is a leaf node.
+    return U->getValue();
   }
   // No Identified object found.
   return 0;
@@ -121,8 +131,8 @@ ScalarEvolutionAliasAnalysis::alias(const Value *A, unsigned ASize,
   // If ScalarEvolution can find an underlying object, form a new query.
   // The correctness of this depends on ScalarEvolution not recognizing
   // inttoptr and ptrtoint operators.
-  Value *AO = GetUnderlyingIdentifiedObject(AS);
-  Value *BO = GetUnderlyingIdentifiedObject(BS);
+  Value *AO = GetBaseValue(AS);
+  Value *BO = GetBaseValue(BS);
   if ((AO && AO != A) || (BO && BO != B))
     if (alias(AO ? AO : A, AO ? ~0u : ASize,
               BO ? BO : B, BO ? ~0u : BSize) == NoAlias)