diff --git a/clang/include/clang/AST/Attr.h b/clang/include/clang/AST/Attr.h
--- a/clang/include/clang/AST/Attr.h
+++ b/clang/include/clang/AST/Attr.h
@@ -374,8 +374,7 @@
 
 inline const StreamingDiagnostic &operator<<(const StreamingDiagnostic &DB,
                                              const Attr *At) {
-  DB.AddTaggedVal(reinterpret_cast<intptr_t>(At),
-                  DiagnosticsEngine::ak_attr);
+  DB.AddTaggedVal(reinterpret_cast<uint64_t>(At), DiagnosticsEngine::ak_attr);
   return DB;
 }
 }  // end namespace clang
diff --git a/clang/include/clang/AST/Decl.h b/clang/include/clang/AST/Decl.h
--- a/clang/include/clang/AST/Decl.h
+++ b/clang/include/clang/AST/Decl.h
@@ -4589,7 +4589,7 @@
 /// into a diagnostic with <<.
 inline const StreamingDiagnostic &operator<<(const StreamingDiagnostic &PD,
                                              const NamedDecl *ND) {
-  PD.AddTaggedVal(reinterpret_cast<intptr_t>(ND),
+  PD.AddTaggedVal(reinterpret_cast<uint64_t>(ND),
                   DiagnosticsEngine::ak_nameddecl);
   return PD;
 }
diff --git a/clang/include/clang/AST/NestedNameSpecifier.h b/clang/include/clang/AST/NestedNameSpecifier.h
--- a/clang/include/clang/AST/NestedNameSpecifier.h
+++ b/clang/include/clang/AST/NestedNameSpecifier.h
@@ -521,7 +521,7 @@
 /// NestedNameSpecifiers into a diagnostic with <<.
 inline const StreamingDiagnostic &operator<<(const StreamingDiagnostic &DB,
                                              NestedNameSpecifier *NNS) {
-  DB.AddTaggedVal(reinterpret_cast<intptr_t>(NNS),
+  DB.AddTaggedVal(reinterpret_cast<uint64_t>(NNS),
                   DiagnosticsEngine::ak_nestednamespec);
   return DB;
 }
diff --git a/clang/include/clang/AST/Type.h b/clang/include/clang/AST/Type.h
--- a/clang/include/clang/AST/Type.h
+++ b/clang/include/clang/AST/Type.h
@@ -7146,7 +7146,7 @@
 /// into a diagnostic with <<.
 inline const StreamingDiagnostic &operator<<(const StreamingDiagnostic &PD,
                                              QualType T) {
-  PD.AddTaggedVal(reinterpret_cast<intptr_t>(T.getAsOpaquePtr()),
+  PD.AddTaggedVal(reinterpret_cast<uint64_t>(T.getAsOpaquePtr()),
                   DiagnosticsEngine::ak_qualtype);
   return PD;
 }
diff --git a/clang/include/clang/Basic/Diagnostic.h b/clang/include/clang/Basic/Diagnostic.h
--- a/clang/include/clang/Basic/Diagnostic.h
+++ b/clang/include/clang/Basic/Diagnostic.h
@@ -164,9 +164,9 @@
   /// The values for the various substitution positions.
   ///
   /// This is used when the argument is not an std::string. The specific value
-  /// is mangled into an intptr_t and the interpretation depends on exactly
+  /// is mangled into an uint64_t and the interpretation depends on exactly
   /// what sort of argument kind it is.
-  intptr_t DiagArgumentsVal[MaxArguments];
+  uint64_t DiagArgumentsVal[MaxArguments];
 
   /// The values for the various substitution positions that have
   /// string arguments.
@@ -1179,7 +1179,7 @@
     DiagStorage = nullptr;
   }
 
-  void AddTaggedVal(intptr_t V, DiagnosticsEngine::ArgumentKind Kind) const {
+  void AddTaggedVal(uint64_t V, DiagnosticsEngine::ArgumentKind Kind) const {
     if (!DiagStorage)
       DiagStorage = getStorage();
 
@@ -1580,18 +1580,18 @@
 
   /// Return the specified signed integer argument.
   /// \pre getArgKind(Idx) == DiagnosticsEngine::ak_sint
-  int getArgSInt(unsigned Idx) const {
+  int64_t getArgSInt(unsigned Idx) const {
     assert(getArgKind(Idx) == DiagnosticsEngine::ak_sint &&
            "invalid argument accessor!");
-    return (int)DiagObj->DiagStorage.DiagArgumentsVal[Idx];
+    return (int64_t)DiagObj->DiagStorage.DiagArgumentsVal[Idx];
   }
 
   /// Return the specified unsigned integer argument.
   /// \pre getArgKind(Idx) == DiagnosticsEngine::ak_uint
-  unsigned getArgUInt(unsigned Idx) const {
+  uint64_t getArgUInt(unsigned Idx) const {
     assert(getArgKind(Idx) == DiagnosticsEngine::ak_uint &&
            "invalid argument accessor!");
-    return (unsigned)DiagObj->DiagStorage.DiagArgumentsVal[Idx];
+    return DiagObj->DiagStorage.DiagArgumentsVal[Idx];
   }
 
   /// Return the specified IdentifierInfo argument.
@@ -1605,7 +1605,7 @@
 
   /// Return the specified non-string argument in an opaque form.
   /// \pre getArgKind(Idx) != DiagnosticsEngine::ak_std_string
-  intptr_t getRawArg(unsigned Idx) const {
+  uint64_t getRawArg(unsigned Idx) const {
     assert(getArgKind(Idx) != DiagnosticsEngine::ak_std_string &&
            "invalid argument accessor!");
     return DiagObj->DiagStorage.DiagArgumentsVal[Idx];
diff --git a/clang/include/clang/Sema/ParsedAttr.h b/clang/include/clang/Sema/ParsedAttr.h
--- a/clang/include/clang/Sema/ParsedAttr.h
+++ b/clang/include/clang/Sema/ParsedAttr.h
@@ -1119,14 +1119,14 @@
 
 inline const StreamingDiagnostic &operator<<(const StreamingDiagnostic &DB,
                                              const ParsedAttr &At) {
-  DB.AddTaggedVal(reinterpret_cast<intptr_t>(At.getAttrName()),
+  DB.AddTaggedVal(reinterpret_cast<uint64_t>(At.getAttrName()),
                   DiagnosticsEngine::ak_identifierinfo);
   return DB;
 }
 
 inline const StreamingDiagnostic &operator<<(const StreamingDiagnostic &DB,
                                              const ParsedAttr *At) {
-  DB.AddTaggedVal(reinterpret_cast<intptr_t>(At->getAttrName()),
+  DB.AddTaggedVal(reinterpret_cast<uint64_t>(At->getAttrName()),
                   DiagnosticsEngine::ak_identifierinfo);
   return DB;
 }
@@ -1141,7 +1141,7 @@
               std::is_same<ACI, AttributeCommonInfo>::value, int> = 0>
 inline const StreamingDiagnostic &operator<<(const StreamingDiagnostic &DB,
                                            const ACI &CI) {
-  DB.AddTaggedVal(reinterpret_cast<intptr_t>(CI.getAttrName()),
+  DB.AddTaggedVal(reinterpret_cast<uint64_t>(CI.getAttrName()),
                   DiagnosticsEngine::ak_identifierinfo);
   return DB;
 }
@@ -1151,7 +1151,7 @@
               std::is_same<ACI, AttributeCommonInfo>::value, int> = 0>
 inline const StreamingDiagnostic &operator<<(const StreamingDiagnostic &DB,
                                            const ACI* CI) {
-  DB.AddTaggedVal(reinterpret_cast<intptr_t>(CI->getAttrName()),
+  DB.AddTaggedVal(reinterpret_cast<uint64_t>(CI->getAttrName()),
                   DiagnosticsEngine::ak_identifierinfo);
   return DB;
 }
diff --git a/clang/lib/Basic/Diagnostic.cpp b/clang/lib/Basic/Diagnostic.cpp
--- a/clang/lib/Basic/Diagnostic.cpp
+++ b/clang/lib/Basic/Diagnostic.cpp
@@ -932,7 +932,7 @@
     }
     // ---- INTEGERS ----
     case DiagnosticsEngine::ak_sint: {
-      int Val = getArgSInt(ArgNo);
+      int64_t Val = getArgSInt(ArgNo);
 
       if (ModifierIs(Modifier, ModifierLen, "select")) {
         HandleSelectModifier(*this, (unsigned)Val, Argument, ArgumentLen,
@@ -951,7 +951,7 @@
       break;
     }
     case DiagnosticsEngine::ak_uint: {
-      unsigned Val = getArgUInt(ArgNo);
+      uint64_t Val = getArgUInt(ArgNo);
 
       if (ModifierIs(Modifier, ModifierLen, "select")) {
         HandleSelectModifier(*this, Val, Argument, ArgumentLen, OutStr);