4 files changed, 21 insertions, 4 deletions
diff --git a/include/llvm/Support/ConstantFolder.h b/include/llvm/Support/ConstantFolder.h
index cb9b055..422d1ad 100644
--- a/include/llvm/Support/ConstantFolder.h
+++ b/include/llvm/Support/ConstantFolder.h
@@ -56,6 +56,9 @@ public:
   Constant *CreateSDiv(Constant *LHS, Constant *RHS) const {
     return ConstantExpr::getSDiv(LHS, RHS);
   }
+  Constant *CreateExactSDiv(Constant *LHS, Constant *RHS) const {
+    return ConstantExpr::getExactSDiv(LHS, RHS);
+  }
   Constant *CreateFDiv(Constant *LHS, Constant *RHS) const {
     return ConstantExpr::getFDiv(LHS, RHS);
   }
diff --git a/include/llvm/Support/IRBuilder.h b/include/llvm/Support/IRBuilder.h
index b2619a5..a8663d2 100644
--- a/include/llvm/Support/IRBuilder.h
+++ b/include/llvm/Support/IRBuilder.h
@@ -241,6 +241,12 @@ public:
         return Folder.CreateSDiv(LC, RC);
     return Insert(BinaryOperator::CreateSDiv(LHS, RHS), Name);
   }
+  Value *CreateExactSDiv(Value *LHS, Value *RHS, const char *Name = "") {
+    if (Constant *LC = dyn_cast<Constant>(LHS))
+      if (Constant *RC = dyn_cast<Constant>(RHS))
+        return Folder.CreateExactSDiv(LC, RC);
+    return Insert(BinaryOperator::CreateExactSDiv(LHS, RHS), Name);
+  }
   Value *CreateFDiv(Value *LHS, Value *RHS, const char *Name = "") {
     if (Constant *LC = dyn_cast<Constant>(LHS))
       if (Constant *RC = dyn_cast<Constant>(RHS))
@@ -719,7 +725,9 @@ public:
 
   /// CreatePtrDiff - Return the i64 difference between two pointer values,
   /// dividing out the size of the pointed-to objects.  This is intended to
-  /// implement C-style pointer subtraction.
+  /// implement C-style pointer subtraction. As such, the pointers must be
+  /// appropriately aligned for their element types and pointing into the
+  /// same object.
   Value *CreatePtrDiff(Value *LHS, Value *RHS, const char *Name = "") {
     assert(LHS->getType() == RHS->getType() &&
            "Pointer subtraction operand types must match!");
@@ -727,9 +735,9 @@ public:
     Value *LHS_int = CreatePtrToInt(LHS, Type::Int64Ty);
     Value *RHS_int = CreatePtrToInt(RHS, Type::Int64Ty);
     Value *Difference = CreateSub(LHS_int, RHS_int);
-    return CreateSDiv(Difference,
-                      ConstantExpr::getSizeOf(ArgType->getElementType()),
-                      Name);
+    return CreateExactSDiv(Difference,
+                           ConstantExpr::getSizeOf(ArgType->getElementType()),
+                           Name);
   }
 };
 
diff --git a/include/llvm/Support/NoFolder.h b/include/llvm/Support/NoFolder.h
index e0fb9cd..b89c084 100644
--- a/include/llvm/Support/NoFolder.h
+++ b/include/llvm/Support/NoFolder.h
@@ -63,6 +63,9 @@ public:
   Value *CreateSDiv(Constant *LHS, Constant *RHS) const {
     return BinaryOperator::CreateSDiv(LHS, RHS);
   }
+  Value *CreateExactSDiv(Constant *LHS, Constant *RHS) const {
+    return BinaryOperator::CreateExactSDiv(LHS, RHS);
+  }
   Value *CreateFDiv(Constant *LHS, Constant *RHS) const {
     return BinaryOperator::CreateFDiv(LHS, RHS);
   }
diff --git a/include/llvm/Support/TargetFolder.h b/include/llvm/Support/TargetFolder.h
index cdcc4a8..900c326 100644
--- a/include/llvm/Support/TargetFolder.h
+++ b/include/llvm/Support/TargetFolder.h
@@ -72,6 +72,9 @@ public:
   Constant *CreateSDiv(Constant *LHS, Constant *RHS) const {
     return Fold(ConstantExpr::getSDiv(LHS, RHS));
   }
+  Constant *CreateExactSDiv(Constant *LHS, Constant *RHS) const {
+    return Fold(ConstantExpr::getExactSDiv(LHS, RHS));
+  }
   Constant *CreateFDiv(Constant *LHS, Constant *RHS) const {
     return Fold(ConstantExpr::getFDiv(LHS, RHS));
   }