--- a/js/src/ion/arm/IonFrames-arm.h
+++ b/js/src/ion/arm/IonFrames-arm.h
@@ -433,17 +433,17 @@ class IonOOLProxyGetExitFrameLayout
 };
 
 class IonDOMExitFrameLayout
 {
     IonExitFooterFrame footer_;
     IonExitFrameLayout exit_;
     JSObject *thisObj;
 
-    // We need to split the Value in 2 field of 32 bits, otherwise the C++
+    // We need to split the Value in 2 fields of 32 bits, otherwise the C++
     // compiler may add some padding between the fields.
     uint32_t loCalleeResult_;
     uint32_t hiCalleeResult_;
 
   public:
     static inline size_t Size() {
         return sizeof(IonDOMExitFrameLayout);
     }
@@ -467,35 +467,38 @@ class IonDOMMethodExitFrameLayout
     IonExitFooterFrame footer_;
     IonExitFrameLayout exit_;
     // This must be the last thing pushed, so as to stay common with
     // IonDOMExitFrameLayout.
     JSObject *thisObj_;
     Value *argv_;
     uintptr_t argc_;
 
-    Value CalleeResult_;
+    // We need to split the Value in 2 fields of 32 bits, otherwise the C++
+    // compiler may add some padding between the fields.
+    uint32_t loCalleeResult_;
+    uint32_t hiCalleeResult_;
 
   public:
     static inline size_t Size() {
         return sizeof(IonDOMMethodExitFrameLayout);
     }
 
     static size_t offsetOfResult() {
-        return offsetof(IonDOMMethodExitFrameLayout, CalleeResult_);
+        return offsetof(IonDOMMethodExitFrameLayout, loCalleeResult_);
     }
     static size_t offsetOfArgcFromArgv() {
         return offsetof(IonDOMMethodExitFrameLayout, argc_) -
             offsetof(IonDOMMethodExitFrameLayout, argv_);
     }
     inline Value *vp() {
         // The code in visitCallDOMNative depends on this static assert holding
-        JS_STATIC_ASSERT(offsetof(IonDOMMethodExitFrameLayout, CalleeResult_) ==
+        JS_STATIC_ASSERT(offsetof(IonDOMMethodExitFrameLayout, loCalleeResult_) ==
                          (offsetof(IonDOMMethodExitFrameLayout, argc_) + sizeof(uintptr_t)));
-        return &CalleeResult_;
+        return reinterpret_cast<Value*>(&loCalleeResult_);
     }
     inline JSObject **thisObjAddress() {
         return &thisObj_;
     }
     inline uintptr_t argc() {
         return argc_;
     }
 };

--- a/js/src/ion/shared/IonFrames-x86-shared.h
+++ b/js/src/ion/shared/IonFrames-x86-shared.h
@@ -398,17 +398,17 @@ class IonOOLProxyGetExitFrameLayout
 
 class IonDOMExitFrameLayout
 {
   protected: // only to silence a clang warning about unused private fields
     IonExitFooterFrame footer_;
     IonExitFrameLayout exit_;
     JSObject *thisObj;
 
-    // We need to split the Value in 2 field of 32 bits, otherwise the C++
+    // We need to split the Value in 2 fields of 32 bits, otherwise the C++
     // compiler may add some padding between the fields.
     uint32_t loCalleeResult_;
     uint32_t hiCalleeResult_;
 
   public:
     static inline size_t Size() {
         return sizeof(IonDOMExitFrameLayout);
     }
@@ -433,35 +433,38 @@ class IonDOMMethodExitFrameLayout
     IonExitFooterFrame footer_;
     IonExitFrameLayout exit_;
     // This must be the last thing pushed, so as to stay common with
     // IonDOMExitFrameLayout.
     JSObject *thisObj_;
     Value *argv_;
     uintptr_t argc_;
 
-    Value CalleeResult_;
+    // We need to split the Value into 2 fields of 32 bits, otherwise the C++
+    // compiler may add some padding between the fields.
+    uint32_t loCalleeResult_;
+    uint32_t hiCalleeResult_;
 
   public:
     static inline size_t Size() {
         return sizeof(IonDOMMethodExitFrameLayout);
     }
 
     static size_t offsetOfResult() {
-        return offsetof(IonDOMMethodExitFrameLayout, CalleeResult_);
+        return offsetof(IonDOMMethodExitFrameLayout, loCalleeResult_);
     }
     static size_t offsetOfArgcFromArgv() {
         return offsetof(IonDOMMethodExitFrameLayout, argc_) -
             offsetof(IonDOMMethodExitFrameLayout, argv_);
     }
 
     inline Value *vp() {
-        JS_STATIC_ASSERT(offsetof(IonDOMMethodExitFrameLayout, CalleeResult_) ==
+        JS_STATIC_ASSERT(offsetof(IonDOMMethodExitFrameLayout, loCalleeResult_) ==
                          (offsetof(IonDOMMethodExitFrameLayout, argc_) + sizeof(uintptr_t)));
-        return &CalleeResult_;
+        return reinterpret_cast<Value*>(&loCalleeResult_);
     }
     inline JSObject **thisObjAddress() {
         return &thisObj_;
     }
     inline uintptr_t argc() {
         return argc_;
     }
 };