1 files changed, 10 insertions, 0 deletions
diff --git a/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp b/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp
index 85da1f4eb..71b6c7cac 100644
--- a/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp
+++ b/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp
@@ -1035,6 +1035,16 @@ RegisterID* BinaryOpNode::emitBytecode(BytecodeGenerator& generator, RegisterID*
 
     RefPtr<RegisterID> src1 = generator.emitNodeForLeftHandSide(m_expr1, m_rightHasAssignments, m_expr2->isPure(generator));
     RegisterID* src2 = generator.emitNode(m_expr2);
+    if (generator.m_lastOpcodeID == op_typeof && (opcodeID == op_neq || opcodeID == op_nstricteq)) {
+        RefPtr<RegisterID> tmp = generator.tempDestination(dst);
+        if (opcodeID == op_neq)
+            generator.emitEqualityOp(op_eq, generator.finalDestination(tmp.get(), src1.get()), src1.get(), src2);
+        else if (opcodeID == op_nstricteq)
+            generator.emitEqualityOp(op_stricteq, generator.finalDestination(tmp.get(), src1.get()), src1.get(), src2);
+        else
+            ASSERT_NOT_REACHED();
+        return generator.emitUnaryOp(op_not, generator.finalDestination(dst, tmp.get()), tmp.get());
+    }
     return generator.emitBinaryOp(opcodeID, generator.finalDestination(dst, src1.get()), src1.get(), src2, OperandTypes(m_expr1->resultDescriptor(), m_expr2->resultDescriptor()));
 }