diff --git a/js/src/methodjit/Compiler.cpp b/js/src/methodjit/Compiler.cpp
index fd1708a01c7..7f9e5c29cab 100644
--- a/js/src/methodjit/Compiler.cpp
+++ b/js/src/methodjit/Compiler.cpp
@@ -1127,6 +1127,13 @@ mjit::Compiler::generateMethod()
           }
           END_CASE(JSOP_CALLDSLOT)
 
+          BEGIN_CASE(JSOP_ARGSUB)
+            prepareStubCall();
+            masm.move(Imm32(GET_ARGNO(PC)), Registers::ArgReg1);
+            stubCall(stubs::ArgSub, Uses(0), Defs(1));
+            frame.pushSynced();
+          END_CASE(JSOP_ARGSUB)
+
           BEGIN_CASE(JSOP_ARGCNT)
             prepareStubCall();
             stubCall(stubs::ArgCnt, Uses(0), Defs(1));
diff --git a/js/src/methodjit/StubCalls.cpp b/js/src/methodjit/StubCalls.cpp
index 36c7967c425..fa807c67f9a 100644
--- a/js/src/methodjit/StubCalls.cpp
+++ b/js/src/methodjit/StubCalls.cpp
@@ -2482,3 +2482,13 @@ stubs::Pos(VMFrame &f)
         THROW();
 }
 
+void JS_FASTCALL
+stubs::ArgSub(VMFrame &f, uint32 n)
+{
+    jsid id = INT_TO_JSID(n);
+    Value rval;
+    if (!js_GetArgsProperty(f.cx, f.fp, id, &rval))
+        THROW();
+    f.regs.sp[0] = rval;
+}
+
diff --git a/js/src/methodjit/StubCalls.h b/js/src/methodjit/StubCalls.h
index 228c373fcc5..27be117af29 100644
--- a/js/src/methodjit/StubCalls.h
+++ b/js/src/methodjit/StubCalls.h
@@ -110,6 +110,7 @@ JSObject * JS_FASTCALL RegExp(VMFrame &f, JSObject *regex);
 JSObject * JS_FASTCALL Lambda(VMFrame &f, JSFunction *fun);
 JSObject * JS_FASTCALL FlatLambda(VMFrame &f, JSFunction *fun);
 void JS_FASTCALL Arguments(VMFrame &f);
+void JS_FASTCALL ArgSub(VMFrame &f, uint32 n);
 void JS_FASTCALL EnterBlock(VMFrame &f, JSObject *obj);
 void JS_FASTCALL LeaveBlock(VMFrame &f);