1 files changed, 15 insertions, 6 deletions

diff --git a/js/src/jit/MIR.h b/js/src/jit/MIR.h
index 9076339f15..ac55b1150b 100644
--- a/js/src/jit/MIR.h
+++ b/js/src/jit/MIR.h
@@ -4043,14 +4043,18 @@ class MCall
     uint32_t numActualArgs_;
 
     // True if the call is for JSOP_NEW.
-    bool construct_;
+    bool construct_:1;
 
-    bool needsArgCheck_;
+    // True if the caller does not use the return value.
+    bool ignoresReturnValue_:1;
 
-    MCall(WrappedFunction* target, uint32_t numActualArgs, bool construct)
+    bool needsArgCheck_:1;
+
+    MCall(WrappedFunction* target, uint32_t numActualArgs, bool construct, bool ignoresReturnValue)
       : target_(target),
         numActualArgs_(numActualArgs),
         construct_(construct),
+        ignoresReturnValue_(ignoresReturnValue),
         needsArgCheck_(true)
     {
         setResultType(MIRType::Value);
@@ -4059,7 +4063,7 @@ class MCall
   public:
     INSTRUCTION_HEADER(Call)
     static MCall* New(TempAllocator& alloc, JSFunction* target, size_t maxArgc, size_t numActualArgs,
-                      bool construct, bool isDOMCall);
+                      bool construct, bool ignoresReturnValue, bool isDOMCall);
 
     void initFunction(MDefinition* func) {
         initOperand(FunctionOperandIndex, func);
@@ -4104,6 +4108,10 @@ class MCall
         return construct_;
     }
 
+    bool ignoresReturnValue() const {
+        return ignoresReturnValue_;
+    }
+
     // The number of stack arguments is the max between the number of formal
     // arguments and the number of actual arguments. The number of stack
     // argument includes the |undefined| padding added in case of underflow.
@@ -4147,7 +4155,7 @@ class MCallDOMNative : public MCall
     // virtual things from MCall.
   protected:
     MCallDOMNative(WrappedFunction* target, uint32_t numActualArgs)
-        : MCall(target, numActualArgs, false)
+        : MCall(target, numActualArgs, false, false)
     {
         MOZ_ASSERT(getJitInfo()->type() != JSJitInfo::InlinableNative);
 
@@ -4162,7 +4170,8 @@ class MCallDOMNative : public MCall
     }
 
     friend MCall* MCall::New(TempAllocator& alloc, JSFunction* target, size_t maxArgc,
-                             size_t numActualArgs, bool construct, bool isDOMCall);
+                             size_t numActualArgs, bool construct, bool ignoresReturnValue,
+                             bool isDOMCall);
 
     const JSJitInfo* getJitInfo() const;
   public: