diff --git a/js/src/methodjit/Compiler.cpp b/js/src/methodjit/Compiler.cpp
index 71f7c54e710..cb8fdaf9099 100644
--- a/js/src/methodjit/Compiler.cpp
+++ b/js/src/methodjit/Compiler.cpp
@@ -474,6 +474,21 @@ mjit::Compiler::generateMethod()
             jsop_binary(op, stubs::Mod);
           END_CASE(JSOP_MOD)
 
+          BEGIN_CASE(JSOP_NEG)
+          {
+            FrameEntry *top = frame.peek(-1);
+            if (top->isConstant() && top->getValue().isPrimitive()) {
+                double d;
+                ValueToNumber(cx, top->getValue(), &d);
+                d = -d;
+                frame.pop();
+                frame.push(DoubleTag(d));
+            } else {
+                jsop_neg();
+            }
+          }
+          END_CASE(JSOP_NEG)
+
           BEGIN_CASE(JSOP_VOID)
             frame.pop();
             frame.push(UndefinedTag());
diff --git a/js/src/methodjit/Compiler.h b/js/src/methodjit/Compiler.h
index 8844636a40c..94c6f3093cc 100644
--- a/js/src/methodjit/Compiler.h
+++ b/js/src/methodjit/Compiler.h
@@ -139,6 +139,7 @@ class Compiler
     void jsop_bitop(JSOp op);
     void jsop_globalinc(JSOp op, uint32 index);
     void jsop_relational(JSOp op, BoolStub stub, jsbytecode *target, JSOp fused);
+    void jsop_neg();
 
 #define STUB_CALL_TYPE(type)                                            \
     Call stubCall(type stub, Uses uses, Defs defs) {                    \
diff --git a/js/src/methodjit/StubCalls.cpp b/js/src/methodjit/StubCalls.cpp
index 729ed7c0f07..9c336053281 100644
--- a/js/src/methodjit/StubCalls.cpp
+++ b/js/src/methodjit/StubCalls.cpp
@@ -1621,3 +1621,13 @@ stubs::This(VMFrame &f)
     f.regs.sp[0] = f.fp->thisv;
 }
 
+void JS_FASTCALL
+stubs::Neg(VMFrame &f)
+{
+    double d;
+    if (!ValueToNumber(f.cx, f.regs.sp[-1], &d))
+        THROW();
+    d = -d;
+    f.regs.sp[-1].setNumber(d);
+}
+
diff --git a/js/src/methodjit/StubCalls.h b/js/src/methodjit/StubCalls.h
index 1fdad8003e1..4258e2b07ab 100644
--- a/js/src/methodjit/StubCalls.h
+++ b/js/src/methodjit/StubCalls.h
@@ -81,6 +81,7 @@ void JS_FASTCALL Sub(VMFrame &f);
 void JS_FASTCALL Mul(VMFrame &f);
 void JS_FASTCALL Div(VMFrame &f);
 void JS_FASTCALL Mod(VMFrame &f);
+void JS_FASTCALL Neg(VMFrame &f);
 
 JSBool JS_FASTCALL ValueToBoolean(VMFrame &f);
 
diff --git a/js/src/methodjit/nunbox/FastOps.cpp b/js/src/methodjit/nunbox/FastOps.cpp
index ef310ee45ad..f65a29b7fce 100644
--- a/js/src/methodjit/nunbox/FastOps.cpp
+++ b/js/src/methodjit/nunbox/FastOps.cpp
@@ -484,3 +484,12 @@ mjit::Compiler::jsop_relational(JSOp op, BoolStub stub, jsbytecode *target, JSOp
     }
 }
 
+void
+mjit::Compiler::jsop_neg()
+{
+    prepareStubCall();
+    stubCall(stubs::Neg, Uses(1), Defs(1));
+    frame.pop();
+    frame.pushSynced();
+}
+