diff --git a/lib/Sema/SemaCXXCast.cpp b/lib/Sema/SemaCXXCast.cpp
index 25ad7b6..baeebe1 100644
--- a/lib/Sema/SemaCXXCast.cpp
+++ b/lib/Sema/SemaCXXCast.cpp
@@ -1131,7 +1131,7 @@
 
   // Is the source an overloaded name? (i.e. &foo)
   // If so, reinterpret_cast can not help us here (13.4, p1, bullet 5)
-  if (SrcType == Self.Context.OverloadTy )
+  if (SrcType == Self.Context.OverloadTy)
     return TC_NotApplicable;
 
   if (const ReferenceType *DestTypeTmp = DestType->getAs<ReferenceType>()) {
@@ -1270,6 +1270,8 @@
     assert(destIsPtr && "One type must be a pointer");
     // C++ 5.2.10p5: A value of integral or enumeration type can be explicitly
     //   converted to a pointer.
+    // C++ 5.2.10p9: [Note: ...a null pointer constant of integral type is not
+    //   necessarily converted to a null pointer value.]
     Kind = CK_IntegralToPointer;
     return TC_Success;
   }
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 8da3846..6eb07b5 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -4003,7 +4003,8 @@
 }
 
 static CastKind getScalarCastKind(ASTContext &Context,
-                                            QualType SrcTy, QualType DestTy) {
+                                  Expr *Src, QualType DestTy) {
+  QualType SrcTy = Src->getType();
   if (Context.hasSameUnqualifiedType(SrcTy, DestTy))
     return CK_NoOp;
 
@@ -4019,8 +4020,11 @@
   if (SrcTy->isIntegerType()) {
     if (DestTy->isIntegerType())
       return CK_IntegralCast;
-    if (DestTy->hasPointerRepresentation())
+    if (DestTy->hasPointerRepresentation()) {
+      if (Src->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNull))
+        return CK_NullToPointer;
       return CK_IntegralToPointer;
+    }
     if (DestTy->isRealFloatingType())
       return CK_IntegralToFloating;
   }
@@ -4131,7 +4135,7 @@
         << castType << castExpr->getSourceRange();
   }
 
-  Kind = getScalarCastKind(Context, castExpr->getType(), castType);
+  Kind = getScalarCastKind(Context, castExpr, castType);
 
   if (Kind == CK_Unknown || Kind == CK_BitCast)
     CheckCastAlign(castExpr, castType, TyR);
@@ -4185,7 +4189,7 @@
 
   QualType DestElemTy = DestTy->getAs<ExtVectorType>()->getElementType();
   ImpCastExprToType(CastExpr, DestElemTy,
-                    getScalarCastKind(Context, SrcTy, DestElemTy));
+                    getScalarCastKind(Context, CastExpr, DestElemTy));
 
   Kind = CK_VectorSplat;
   return false;
@@ -4533,7 +4537,8 @@
     return LHSTy;
   }
 
-  // GCC compatibility: soften pointer/integer mismatch.
+  // GCC compatibility: soften pointer/integer mismatch.  Note that
+  // null pointers have been filtered out by this point.
   if (RHSTy->isPointerType() && LHSTy->isIntegerType()) {
     Diag(QuestionLoc, diag::warn_typecheck_cond_pointer_integer_mismatch)
       << LHSTy << RHSTy << LHS->getSourceRange() << RHS->getSourceRange();
@@ -5104,7 +5109,7 @@
 
       if (rExpr->isNullPointerConstant(Context,
                                        Expr::NPC_ValueDependentIsNull)) {
-        ImpCastExprToType(rExpr, it->getType(), CK_IntegralToPointer);
+        ImpCastExprToType(rExpr, it->getType(), CK_NullToPointer);
         InitField = *it;
         break;
       }
@@ -5827,7 +5832,7 @@
       ImpCastExprToType(rex, lType, 
                         lType->isMemberPointerType()
                           ? CK_NullToMemberPointer
-                          : CK_IntegralToPointer);
+                          : CK_NullToPointer);
       return ResultTy;
     }
     if (LHSIsNull &&
@@ -5836,7 +5841,7 @@
       ImpCastExprToType(lex, rType, 
                         rType->isMemberPointerType()
                           ? CK_NullToMemberPointer
-                          : CK_IntegralToPointer);
+                          : CK_NullToPointer);
       return ResultTy;
     }
 
@@ -5951,21 +5956,23 @@
     }
     
     if (lType->isIntegerType())
-      ImpCastExprToType(lex, rType, CK_IntegralToPointer);
+      ImpCastExprToType(lex, rType,
+                        LHSIsNull ? CK_NullToPointer : CK_IntegralToPointer);
     else
-      ImpCastExprToType(rex, lType, CK_IntegralToPointer);
+      ImpCastExprToType(rex, lType,
+                        RHSIsNull ? CK_NullToPointer : CK_IntegralToPointer);
     return ResultTy;
   }
   
   // Handle block pointers.
   if (!isRelational && RHSIsNull
       && lType->isBlockPointerType() && rType->isIntegerType()) {
-    ImpCastExprToType(rex, lType, CK_IntegralToPointer);
+    ImpCastExprToType(rex, lType, CK_NullToPointer);
     return ResultTy;
   }
   if (!isRelational && LHSIsNull
       && lType->isIntegerType() && rType->isBlockPointerType()) {
-    ImpCastExprToType(lex, rType, CK_IntegralToPointer);
+    ImpCastExprToType(lex, rType, CK_NullToPointer);
     return ResultTy;
   }
   return InvalidOperands(Loc, lex, rex);
diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index e58c38c..b6a0251 100644
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -2750,14 +2750,14 @@
     if (T2->isMemberPointerType())
       ImpCastExprToType(E1, T2, CK_NullToMemberPointer);
     else
-      ImpCastExprToType(E1, T2, CK_IntegralToPointer);
+      ImpCastExprToType(E1, T2, CK_NullToPointer);
     return T2;
   }
   if (E2->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNull)) {
     if (T1->isMemberPointerType())
       ImpCastExprToType(E2, T1, CK_NullToMemberPointer);
     else
-      ImpCastExprToType(E2, T1, CK_IntegralToPointer);
+      ImpCastExprToType(E2, T1, CK_NullToPointer);
     return T1;
   }
 
diff --git a/lib/Sema/SemaExprObjC.cpp b/lib/Sema/SemaExprObjC.cpp
index 5ddf945..be87a42 100644
--- a/lib/Sema/SemaExprObjC.cpp
+++ b/lib/Sema/SemaExprObjC.cpp
@@ -1014,9 +1014,13 @@
         if (ReceiverType->isPointerType())
           ImpCastExprToType(Receiver, Context.getObjCIdType(), 
                             CK_BitCast);
-        else
+        else {
+          // TODO: specialized warning on null receivers?
+          bool IsNull = Receiver->isNullPointerConstant(Context,
+                                              Expr::NPC_ValueDependentIsNull);
           ImpCastExprToType(Receiver, Context.getObjCIdType(),
-                            CK_IntegralToPointer);
+                            IsNull ? CK_NullToPointer : CK_IntegralToPointer);
+        }
         ReceiverType = Receiver->getType();
       } 
       else if (getLangOptions().CPlusPlus &&