Revert changes to MemoryBuiltins.h and make a more limited change

Author: hvdijk

llvm/include/llvm/Analysis/MemoryBuiltins.h

@@ -222,43 +222,21 @@ struct SizeOffsetAPInt : public SizeOffsetType<APInt, SizeOffsetAPInt> {
   static bool known(const APInt &V) { return V.getBitWidth() > 1; }
 };
 
-/// OffsetSpan - Used internally by \p ObjectSizeOffsetVisitor. Represents a
-/// point in memory as a pair of allocated bytes before and after it.
-struct OffsetSpan {
-  APInt Before; /// Number of allocated bytes before this point.
-  APInt After;  /// Number of allocated bytes after this point.
-
-  OffsetSpan() = default;
-  OffsetSpan(APInt Before, APInt After) : Before(Before), After(After) {}
-
-  bool knownBefore() const { return known(Before); }
-  bool knownAfter() const { return known(After); }
-  bool anyKnown() const { return knownBefore() || knownAfter(); }
-  bool bothKnown() const { return knownBefore() && knownAfter(); }
-
-  bool operator==(const OffsetSpan &RHS) const {
-    return Before == RHS.Before && After == RHS.After;
-  }
-  bool operator!=(const OffsetSpan &RHS) const { return !(*this == RHS); }
-
-  static bool known(const APInt &V) { return V.getBitWidth() > 1; }
-};
-
 /// Evaluate the size and offset of an object pointed to by a Value*
 /// statically. Fails if size or offset are not known at compile time.
 class ObjectSizeOffsetVisitor
-    : public InstVisitor<ObjectSizeOffsetVisitor, OffsetSpan> {
+    : public InstVisitor<ObjectSizeOffsetVisitor, SizeOffsetAPInt> {
   const DataLayout &DL;
   const TargetLibraryInfo *TLI;
   ObjectSizeOpts Options;
   unsigned IntTyBits;
   APInt Zero;
-  SmallDenseMap<Instruction *, OffsetSpan, 8> SeenInsts;
+  SmallDenseMap<Instruction *, SizeOffsetAPInt, 8> SeenInsts;
   unsigned InstructionsVisited;
 
   APInt align(APInt Size, MaybeAlign Align);
 
-  static OffsetSpan unknown() { return OffsetSpan(); }
+  static SizeOffsetAPInt unknown() { return SizeOffsetAPInt(); }
 
 public:
   ObjectSizeOffsetVisitor(const DataLayout &DL, const TargetLibraryInfo *TLI,
@@ -268,30 +246,29 @@ class ObjectSizeOffsetVisitor
 
   // These are "private", except they can't actually be made private. Only
   // compute() should be used by external users.
-  OffsetSpan visitAllocaInst(AllocaInst &I);
-  OffsetSpan visitArgument(Argument &A);
-  OffsetSpan visitCallBase(CallBase &CB);
-  OffsetSpan visitConstantPointerNull(ConstantPointerNull &);
-  OffsetSpan visitExtractElementInst(ExtractElementInst &I);
-  OffsetSpan visitExtractValueInst(ExtractValueInst &I);
-  OffsetSpan visitGlobalAlias(GlobalAlias &GA);
-  OffsetSpan visitGlobalVariable(GlobalVariable &GV);
-  OffsetSpan visitIntToPtrInst(IntToPtrInst &);
-  OffsetSpan visitLoadInst(LoadInst &I);
-  OffsetSpan visitPHINode(PHINode &);
-  OffsetSpan visitSelectInst(SelectInst &I);
-  OffsetSpan visitUndefValue(UndefValue &);
-  OffsetSpan visitInstruction(Instruction &I);
+  SizeOffsetAPInt visitAllocaInst(AllocaInst &I);
+  SizeOffsetAPInt visitArgument(Argument &A);
+  SizeOffsetAPInt visitCallBase(CallBase &CB);
+  SizeOffsetAPInt visitConstantPointerNull(ConstantPointerNull &);
+  SizeOffsetAPInt visitExtractElementInst(ExtractElementInst &I);
+  SizeOffsetAPInt visitExtractValueInst(ExtractValueInst &I);
+  SizeOffsetAPInt visitGlobalAlias(GlobalAlias &GA);
+  SizeOffsetAPInt visitGlobalVariable(GlobalVariable &GV);
+  SizeOffsetAPInt visitIntToPtrInst(IntToPtrInst &);
+  SizeOffsetAPInt visitLoadInst(LoadInst &I);
+  SizeOffsetAPInt visitPHINode(PHINode &);
+  SizeOffsetAPInt visitSelectInst(SelectInst &I);
+  SizeOffsetAPInt visitUndefValue(UndefValue &);
+  SizeOffsetAPInt visitInstruction(Instruction &I);
 
 private:
-  OffsetSpan
-  findLoadOffsetRange(LoadInst &LoadFrom, BasicBlock &BB,
-                      BasicBlock::iterator From,
-                      SmallDenseMap<BasicBlock *, OffsetSpan, 8> &VisitedBlocks,
-                      unsigned &ScannedInstCount);
-  OffsetSpan combineOffsetRange(OffsetSpan LHS, OffsetSpan RHS);
-  OffsetSpan computeImpl(Value *V);
-  OffsetSpan computeValue(Value *V);
+  SizeOffsetAPInt findLoadSizeOffset(
+      LoadInst &LoadFrom, BasicBlock &BB, BasicBlock::iterator From,
+      SmallDenseMap<BasicBlock *, SizeOffsetAPInt, 8> &VisitedBlocks,
+      unsigned &ScannedInstCount);
+  SizeOffsetAPInt combineSizeOffset(SizeOffsetAPInt LHS, SizeOffsetAPInt RHS);
+  SizeOffsetAPInt computeImpl(Value *V);
+  SizeOffsetAPInt computeValue(Value *V);
   bool CheckedZextOrTrunc(APInt &I);
 };