diff --git a/js/src/ion/CodeGenerator.cpp b/js/src/ion/CodeGenerator.cpp
index fb568b1403b6..8d7474104241 100644
--- a/js/src/ion/CodeGenerator.cpp
+++ b/js/src/ion/CodeGenerator.cpp
@@ -2010,6 +2010,46 @@ CodeGenerator::visitInitProp(LInitProp *lir)
     return callVM(InitPropInfo, lir);
 }
 
+typedef bool (*CreateThisFn)(JSContext *cx, HandleObject callee, MutableHandleValue rval);
+static const VMFunction CreateThisInfo =
+FunctionInfo<CreateThisFn>(CreateThis);
+
+bool
+CodeGenerator::visitCreateThis(LCreateThis *lir)
+{
+    const LAllocation *callee = lir->getCallee();
+
+    if (callee->isConstant())
+        pushArg(ImmGCPtr(&callee->toConstant()->toObject()));
+    else
+        pushArg(ToRegister(callee));
+
+    return callVM(CreateThisInfo, lir);
+}
+
+typedef JSObject *(*CreateThisWithProtoFn)(JSContext *cx, HandleObject callee, JSObject *proto);
+static const VMFunction CreateThisWithProtoInfo =
+FunctionInfo<CreateThisWithProtoFn>(js_CreateThisForFunctionWithProto);
+
+bool
+CodeGenerator::visitCreateThisWithProto(LCreateThisWithProto *lir)
+{
+    const LAllocation *callee = lir->getCallee();
+    const LAllocation *proto = lir->getPrototype();
+
+    if (proto->isConstant())
+        pushArg(ImmGCPtr(&proto->toConstant()->toObject()));
+    else
+        pushArg(ToRegister(proto));
+
+    if (callee->isConstant())
+        pushArg(ImmGCPtr(&callee->toConstant()->toObject()));
+    else
+        pushArg(ToRegister(callee));
+
+    return callVM(CreateThisWithProtoInfo, lir);
+}
+
 typedef JSObject *(*NewGCThingFn)(JSContext *cx, gc::AllocKind allocKind, size_t thingSize);
 static const VMFunction NewGCThingInfo =
     FunctionInfo<NewGCThingFn>(js::ion::NewGCThing);
@@ -2038,59 +2078,6 @@ CodeGenerator::visitCreateThisWithTemplate(LCreateThisWithTemplate *lir)
     return true;
 }
 
-typedef JSObject *(*CreateThisFn)(JSContext *cx, HandleObject callee, JSObject *proto);
-static const VMFunction CreateThisInfo =
-    FunctionInfo<CreateThisFn>(js_CreateThisForFunctionWithProto);
-
-bool
-CodeGenerator::emitCreateThisVM(LInstruction *lir,
-                                const LAllocation *proto,
-                                const LAllocation *callee)
-{
-    if (proto->isConstant())
-        pushArg(ImmGCPtr(&proto->toConstant()->toObject()));
-    else
-        pushArg(ToRegister(proto));
-
-    if (callee->isConstant())
-        pushArg(ImmGCPtr(&callee->toConstant()->toObject()));
-    else
-        pushArg(ToRegister(callee));
-
-    return callVM(CreateThisInfo, lir);
-}
-
-bool
-CodeGenerator::visitCreateThisV(LCreateThisV *lir)
-{
-    Label done, vm;
-
-    const LAllocation *proto = lir->getPrototype();
-    const LAllocation *callee = lir->getCallee();
-
-    // When callee could be a native, put MagicValue in return operand.
-    // Use the VMCall when callee turns out to not be a native.
-    masm.branchIfInterpreted(ToRegister(callee), &vm);
-    masm.moveValue(MagicValue(JS_IS_CONSTRUCTING), GetValueOutput(lir));
-    masm.jump(&done);
-
-    masm.bind(&vm);
-    if (!emitCreateThisVM(lir, proto, callee))
-        return false;
-
-    masm.tagValue(JSVAL_TYPE_OBJECT, ReturnReg, GetValueOutput(lir));
-
-    masm.bind(&done);
-
-    return true;
-}
-
-bool
-CodeGenerator::visitCreateThisO(LCreateThisO *lir)
-{
-    return emitCreateThisVM(lir, lir->getPrototype(), lir->getCallee());
-}
-
 bool
 CodeGenerator::visitReturnFromCtor(LReturnFromCtor *lir)
 {
diff --git a/js/src/ion/CodeGenerator.h b/js/src/ion/CodeGenerator.h
index 096f3c1a738d..96918b7f78f0 100644
--- a/js/src/ion/CodeGenerator.h
+++ b/js/src/ion/CodeGenerator.h
@@ -99,9 +99,8 @@ class CodeGenerator : public CodeGeneratorSpecific
     bool visitNewCallObject(LNewCallObject *lir);
     bool visitNewStringObject(LNewStringObject *lir);
     bool visitInitProp(LInitProp *lir);
-    bool emitCreateThisVM(LInstruction *lir, const LAllocation *proto, const LAllocation *callee);
-    bool visitCreateThisV(LCreateThisV *lir);
-    bool visitCreateThisO(LCreateThisO *lir);
+    bool visitCreateThis(LCreateThis *lir);
+    bool visitCreateThisWithProto(LCreateThisWithProto *lir);
     bool visitCreateThisWithTemplate(LCreateThisWithTemplate *lir);
     bool visitReturnFromCtor(LReturnFromCtor *lir);
     bool visitArrayLength(LArrayLength *lir);
diff --git a/js/src/ion/IonBuilder.cpp b/js/src/ion/IonBuilder.cpp
index c9957be7d651..69de552e16fd 100644
--- a/js/src/ion/IonBuilder.cpp
+++ b/js/src/ion/IonBuilder.cpp
@@ -3574,15 +3574,6 @@ IonBuilder::createCallObject(MDefinition *callee, MDefinition *scope)
     return callObj;
 }
 
-MDefinition *
-IonBuilder::createThisNative()
-{
-    // Native constructors build the new Object themselves.
-    MConstant *magic = MConstant::New(MagicValue(JS_IS_CONSTRUCTING));
-    current->add(magic);
-    return magic;
-}
-
 MDefinition *
 IonBuilder::createThisScripted(MDefinition *callee)
 {
@@ -3610,7 +3601,7 @@ IonBuilder::createThisScripted(MDefinition *callee)
     current->add(getProto);
 
     // Create this from prototype
-    MCreateThis *createThis = MCreateThis::New(callee, getProto);
+    MCreateThisWithProto *createThis = MCreateThisWithProto::New(callee, getProto);
     current->add(createThis);
 
     return createThis;
@@ -3633,8 +3624,13 @@ IonBuilder::getSingletonPrototype(JSFunction *target)
 }
 
 MDefinition *
-IonBuilder::createThisScriptedSingleton(HandleFunction target, HandleObject proto, MDefinition *callee)
+IonBuilder::createThisScriptedSingleton(HandleFunction target, MDefinition *callee)
 {
+    // Get the singleton prototype (if exists)
+    RootedObject proto(cx, getSingletonPrototype(target));
+    if (!proto)
+        return NULL;
+
     // Generate an inline path to create a new |this| object with
     // the given singleton prototype.
     types::TypeObject *type = proto->getNewType(cx, target);
@@ -3661,36 +3657,26 @@ MDefinition *
 IonBuilder::createThis(HandleFunction target, MDefinition *callee)
 {
     // Create this for unknown target
-    if (!target)
-        return createThisScripted(callee);
-
-    // Create this for native function
-    if (target->isNative()) {
-        if (!target->isNativeConstructor())
-            return NULL;
-        return createThisNative();
+    if (!target) {
+        MCreateThis *createThis = MCreateThis::New(callee);
+        current->add(createThis);
+        return createThis;
     }
 
-    // Create this with known prototype.
-    RootedObject proto(cx, getSingletonPrototype(target));
+    // Native constructors build the new Object themselves.
+    if (target->isNative()) {
+        JS_ASSERT (target->isNativeConstructor());
+        MConstant *magic = MConstant::New(MagicValue(JS_IS_CONSTRUCTING));
+        current->add(magic);
+        return magic;
+    }
 
     // Try baking in the prototype.
-    if (proto) {
-        MDefinition *createThis = createThisScriptedSingleton(target, proto, callee);
-        if (createThis)
-            return createThis;
-    }
+    MDefinition *createThis = createThisScriptedSingleton(target, callee);
+    if (createThis)
+        return createThis;
 
-    MDefinition *createThis = createThisScripted(callee);
-    if (!createThis)
-        return NULL;
-
-    // The native function case is already handled upfront.
-    // Here we can safely remove the native check for MCreateThis.
-    JS_ASSERT(createThis->isCreateThis());
-    createThis->toCreateThis()->removeNativeCheck();
-
-    return createThis;
+    return createThisScripted(callee);
 }
 
 bool
diff --git a/js/src/ion/IonBuilder.h b/js/src/ion/IonBuilder.h
index c8a59d83bfc4..0a490503aa96 100644
--- a/js/src/ion/IonBuilder.h
+++ b/js/src/ion/IonBuilder.h
@@ -275,9 +275,8 @@ class IonBuilder : public MIRGenerator
 
     JSObject *getSingletonPrototype(JSFunction *target);
 
-    MDefinition *createThisNative();
     MDefinition *createThisScripted(MDefinition *callee);
-    MDefinition *createThisScriptedSingleton(HandleFunction target, HandleObject proto, MDefinition *callee);
+    MDefinition *createThisScriptedSingleton(HandleFunction target, MDefinition *callee);
     MDefinition *createThis(HandleFunction target, MDefinition *callee);
     MInstruction *createDeclEnvObject(MDefinition *callee, MDefinition *scopeObj);
     MInstruction *createCallObject(MDefinition *callee, MDefinition *scopeObj);
diff --git a/js/src/ion/LIR-Common.h b/js/src/ion/LIR-Common.h
index 07f90291251c..b51f1c264911 100644
--- a/js/src/ion/LIR-Common.h
+++ b/js/src/ion/LIR-Common.h
@@ -432,6 +432,52 @@ class LToIdV : public LCallInstructionHelper<BOX_PIECES, 2 * BOX_PIECES, 0>
     }
 };
 
+// Allocate an object for |new| on the caller-side,
+// when there is no templateObject or prototype known
+class LCreateThis : public LCallInstructionHelper<BOX_PIECES, 1, 0>
+{
+  public:
+    LIR_HEADER(CreateThis)
+
+    LCreateThis(const LAllocation &callee)
+    {
+        setOperand(0, callee);
+    }
+
+    const LAllocation *getCallee() {
+        return getOperand(0);
+    }
+
+    MCreateThis *mir() const {
+        return mir_->toCreateThis();
+    }
+};
+
+// Allocate an object for |new| on the caller-side,
+// when the prototype is known.
+class LCreateThisWithProto : public LCallInstructionHelper<1, 2, 0>
+{
+  public:
+    LIR_HEADER(CreateThisWithProto)
+
+    LCreateThisWithProto(const LAllocation &callee, const LAllocation &prototype)
+    {
+        setOperand(0, callee);
+        setOperand(1, prototype);
+    }
+
+    const LAllocation *getCallee() {
+        return getOperand(0);
+    }
+    const LAllocation *getPrototype() {
+        return getOperand(1);
+    }
+
+    MCreateThis *mir() const {
+        return mir_->toCreateThis();
+    }
+};
+
 // Allocate an object for |new| on the caller-side.
 // Always performs object initialization with a fast path.
 class LCreateThisWithTemplate : public LInstructionHelper<1, 0, 0>
@@ -447,54 +493,6 @@ class LCreateThisWithTemplate : public LInstructionHelper<1, 0, 0>
     }
 };
 
-// Allocate an object for |new| on the caller-side, when there is no templateObject.
-class LCreateThisV : public LCallInstructionHelper<BOX_PIECES, 2, 0>
-{
-  public:
-    LIR_HEADER(CreateThisV)
-
-    LCreateThisV(const LAllocation &callee, const LAllocation &prototype)
-    {
-        setOperand(0, callee);
-        setOperand(1, prototype);
-    }
-
-    const LAllocation *getCallee() {
-        return getOperand(0);
-    }
-    const LAllocation *getPrototype() {
-        return getOperand(1);
-    }
-
-    MCreateThis *mir() const {
-        return mir_->toCreateThis();
-    }
-};
-
-// Allocate an object for |new| on the caller-side, when there is no templateObject.
-class LCreateThisO : public LCallInstructionHelper<1, 2, 0>
-{
-  public:
-    LIR_HEADER(CreateThisO)
-
-    LCreateThisO(const LAllocation &callee, const LAllocation &prototype)
-    {
-        setOperand(0, callee);
-        setOperand(1, prototype);
-    }
-
-    const LAllocation *getCallee() {
-        return getOperand(0);
-    }
-    const LAllocation *getPrototype() {
-        return getOperand(1);
-    }
-
-    MCreateThis *mir() const {
-        return mir_->toCreateThis();
-    }
-};
-
 // If the Value is an Object, return unbox(Value).
 // Otherwise, return the other Object.
 class LReturnFromCtor : public LInstructionHelper<1, BOX_PIECES + 1, 0>
diff --git a/js/src/ion/LOpcodes.h b/js/src/ion/LOpcodes.h
index 8df6a3ec9bd7..a1dbecb5e3cf 100644
--- a/js/src/ion/LOpcodes.h
+++ b/js/src/ion/LOpcodes.h
@@ -39,8 +39,8 @@
     _(ApplyArgsGeneric)             \
     _(StackArgT)                    \
     _(StackArgV)                    \
-    _(CreateThisV)                  \
-    _(CreateThisO)                  \
+    _(CreateThis)                   \
+    _(CreateThisWithProto)          \
     _(CreateThisWithTemplate)       \
     _(ReturnFromCtor)               \
     _(BitNotI)                      \
diff --git a/js/src/ion/Lowering.cpp b/js/src/ion/Lowering.cpp
index b791dbfcf4f6..47b79ec14d67 100644
--- a/js/src/ion/Lowering.cpp
+++ b/js/src/ion/Lowering.cpp
@@ -241,18 +241,19 @@ LIRGenerator::visitCreateThisWithTemplate(MCreateThisWithTemplate *ins)
     return define(lir, ins) && assignSafepoint(lir, ins);
 }
 
+bool
+LIRGenerator::visitCreateThisWithProto(MCreateThisWithProto *ins)
+{
+    LCreateThisWithProto *lir =
+        new LCreateThisWithProto(useRegisterOrConstantAtStart(ins->getCallee()),
+                                 useRegisterOrConstantAtStart(ins->getPrototype()));
+    return defineReturn(lir, ins) && assignSafepoint(lir, ins);
+}
+
 bool
 LIRGenerator::visitCreateThis(MCreateThis *ins)
 {
-    if (ins->needNativeCheck()) {
-        JS_ASSERT(ins->type() == MIRType_Value);
-        LCreateThisV *lir = new LCreateThisV(useRegisterAtStart(ins->getCallee()),
-                                             useRegisterOrConstantAtStart(ins->getPrototype()));
-        return defineReturn(lir, ins) && assignSafepoint(lir, ins);
-    }
-
-    LCreateThisO *lir = new LCreateThisO(useRegisterOrConstantAtStart(ins->getCallee()),
-                                         useRegisterOrConstantAtStart(ins->getPrototype()));
+    LCreateThis *lir = new LCreateThis(useRegisterOrConstantAtStart(ins->getCallee()));
     return defineReturn(lir, ins) && assignSafepoint(lir, ins);
 }
 
diff --git a/js/src/ion/Lowering.h b/js/src/ion/Lowering.h
index bfbde745ee31..372f016a776b 100644
--- a/js/src/ion/Lowering.h
+++ b/js/src/ion/Lowering.h
@@ -91,6 +91,7 @@ class LIRGenerator : public LIRGeneratorSpecific
     bool visitPrepareCall(MPrepareCall *ins);
     bool visitPassArg(MPassArg *arg);
     bool visitCreateThisWithTemplate(MCreateThisWithTemplate *ins);
+    bool visitCreateThisWithProto(MCreateThisWithProto *ins);
     bool visitCreateThis(MCreateThis *ins);
     bool visitReturnFromCtor(MReturnFromCtor *ins);
     bool visitCall(MCall *call);
diff --git a/js/src/ion/MIR.h b/js/src/ion/MIR.h
index 2c20d0a1ad48..4b7f1d742a2c 100644
--- a/js/src/ion/MIR.h
+++ b/js/src/ion/MIR.h
@@ -1688,29 +1688,21 @@ class MCreateThisWithTemplate
 
 // Caller-side allocation of |this| for |new|:
 // Given a prototype operand, construct |this| for JSOP_NEW.
-// For native constructors, returns MagicValue(JS_IS_CONSTRUCTING).
-class MCreateThis
-  : public MAryInstruction<2>,
+class MCreateThisWithProto
+  : public MBinaryInstruction,
     public MixPolicy<ObjectPolicy<0>, ObjectPolicy<1> >
 {
-    bool needNativeCheck_;
-
-    MCreateThis(MDefinition *callee, MDefinition *prototype)
-      : needNativeCheck_(true)
+    MCreateThisWithProto(MDefinition *callee, MDefinition *prototype)
+      : MBinaryInstruction(callee, prototype)
     {
-        initOperand(0, callee);
-        initOperand(1, prototype);
-
-        // Type is mostly object, except for native constructors
-        // therefore the need of Value type.
-        setResultType(MIRType_Value);
+        setResultType(MIRType_Object);
     }
 
   public:
-    INSTRUCTION_HEADER(CreateThis)
-    static MCreateThis *New(MDefinition *callee, MDefinition *prototype)
+    INSTRUCTION_HEADER(CreateThisWithProto)
+    static MCreateThisWithProto *New(MDefinition *callee, MDefinition *prototype)
     {
-        return new MCreateThis(callee, prototype);
+        return new MCreateThisWithProto(callee, prototype);
     }
 
     MDefinition *getCallee() const {
@@ -1719,12 +1711,37 @@ class MCreateThis
     MDefinition *getPrototype() const {
         return getOperand(1);
     }
-    void removeNativeCheck() {
-        needNativeCheck_ = false;
-        setResultType(MIRType_Object);
+
+    // Although creation of |this| modifies global state, it is safely repeatable.
+    AliasSet getAliasSet() const {
+        return AliasSet::None();
     }
-    bool needNativeCheck() const {
-        return needNativeCheck_;
+    TypePolicy *typePolicy() {
+        return this;
+    }
+};
+
+// Caller-side allocation of |this| for |new|:
+// Constructs |this| when possible, else MagicValue(JS_IS_CONSTRUCTING).
+class MCreateThis
+  : public MUnaryInstruction,
+    public ObjectPolicy<0>
+{
+    MCreateThis(MDefinition *callee)
+      : MUnaryInstruction(callee)
+    {
+        setResultType(MIRType_Value);
+    }
+
+  public:
+    INSTRUCTION_HEADER(CreateThis)
+    static MCreateThis *New(MDefinition *callee)
+    {
+        return new MCreateThis(callee);
+    }
+
+    MDefinition *getCallee() const {
+        return getOperand(0);
     }
 
     // Although creation of |this| modifies global state, it is safely repeatable.
diff --git a/js/src/ion/MOpcodes.h b/js/src/ion/MOpcodes.h
index bddade367e82..c8e4724f0a44 100644
--- a/js/src/ion/MOpcodes.h
+++ b/js/src/ion/MOpcodes.h
@@ -31,6 +31,7 @@ namespace ion {
     _(DefVar)                                                               \
     _(DefFun)                                                               \
     _(CreateThis)                                                           \
+    _(CreateThisWithProto)                                                  \
     _(CreateThisWithTemplate)                                               \
     _(PrepareCall)                                                          \
     _(PassArg)                                                              \
diff --git a/js/src/ion/VMFunctions.cpp b/js/src/ion/VMFunctions.cpp
index 504da74f3849..745f6e3f4eae 100644
--- a/js/src/ion/VMFunctions.cpp
+++ b/js/src/ion/VMFunctions.cpp
@@ -437,18 +437,21 @@ NewStringObject(JSContext *cx, HandleString str)
     return StringObject::create(cx, str);
 }
 
-bool SPSEnter(JSContext *cx, HandleScript script)
+bool
+SPSEnter(JSContext *cx, HandleScript script)
 {
     return cx->runtime->spsProfiler.enter(cx, script, script->function());
 }
 
-bool SPSExit(JSContext *cx, HandleScript script)
+bool
+SPSExit(JSContext *cx, HandleScript script)
 {
     cx->runtime->spsProfiler.exit(cx, script, script->function());
     return true;
 }
 
-bool OperatorIn(JSContext *cx, HandleValue key, HandleObject obj, JSBool *out)
+bool
+OperatorIn(JSContext *cx, HandleValue key, HandleObject obj, JSBool *out)
 {
     RootedValue dummy(cx); // Disregards atomization changes: no way to propagate.
     RootedId id(cx);
@@ -464,10 +467,25 @@ bool OperatorIn(JSContext *cx, HandleValue key, HandleObject obj, JSBool *out)
     return true;
 }
 
-bool GetIntrinsicValue(JSContext *cx, HandlePropertyName name, MutableHandleValue rval)
+bool
+GetIntrinsicValue(JSContext *cx, HandlePropertyName name, MutableHandleValue rval)
 {
     return cx->global()->getIntrinsicValue(cx, name, rval);
 }
 
+bool
+CreateThis(JSContext *cx, HandleObject callee, MutableHandleValue rval)
+{
+    rval.set(MagicValue(JS_IS_CONSTRUCTING));
+
+    if (callee->isFunction()) {
+        JSFunction *fun = callee->toFunction();
+        if (fun->isInterpreted())
+            rval.set(ObjectValue(*js_CreateThisForFunction(cx, callee, false)));
+    }
+
+    return true;
+}
+
 } // namespace ion
 } // namespace js
diff --git a/js/src/ion/VMFunctions.h b/js/src/ion/VMFunctions.h
index 7e3f833dd1e4..e09e23d22611 100644
--- a/js/src/ion/VMFunctions.h
+++ b/js/src/ion/VMFunctions.h
@@ -464,6 +464,7 @@ bool OperatorIn(JSContext *cx, HandleValue key, HandleObject obj, JSBool *out);
 
 bool GetIntrinsicValue(JSContext *cx, HandlePropertyName name, MutableHandleValue rval);
 
+bool CreateThis(JSContext *cx, HandleObject callee, MutableHandleValue rval);
 } // namespace ion
 } // namespace js
 
diff --git a/js/src/jit-test/tests/ion/bug825705.js b/js/src/jit-test/tests/ion/bug825705.js
new file mode 100644
index 000000000000..05689f6edec0
--- /dev/null
+++ b/js/src/jit-test/tests/ion/bug825705.js
@@ -0,0 +1,23 @@
+// Test 1: When constructing x, we shouldn't take the prototype for this.
+// it will crash if that happens
+evalcx("\
+    var x = newGlobal().Object;\
+    function f() { return new x; }\
+    f();\
+    f();\
+", newGlobal());
+
+// Test 2: Don't take the prototype of proxy's to create |this|,
+// as this will throw... Not expected behaviour.
+var O = new Proxy(function() {}, {
+    get: function() {
+	    throw "get trap";
+    }
+});
+
+function f() {
+  new O();
+}
+
+f();
+f();