Improve delete property with undefined base (#3312)

This patch finally resolves #2891 also the removes the related bytecode since it has become unnecessary.

JerryScript-DCO-1.0-Signed-off-by: Robert Fancsik frobert@inf.u-szeged.hu

jerry-core/vm/opcodes.c

@@ -176,10 +176,12 @@ vm_op_delete_prop (ecma_value_t object, /**< base object */
                    ecma_value_t property, /**< property name */
                    bool is_strict) /**< strict mode */
 {
+#if !ENABLED (JERRY_ES2015)
   if (ecma_is_value_undefined (object))
   {
     return ECMA_VALUE_TRUE;
   }
+#endif /* !ENABLED (JERRY_ES2015) */
 
   ecma_value_t check_coercible = ecma_op_check_object_coercible (object);
   if (ECMA_IS_VALUE_ERROR (check_coercible))

jerry-core/vm/vm.c

@@ -1917,13 +1917,6 @@ vm_loop (vm_frame_ctx_t *frame_ctx_p) /**< frame context */
 #endif /* ENABLED (JERRY_ES2015) */
           continue;
         }
-        case VM_OC_PUSH_UNDEFINED_BASE:
-        {
-          stack_top_p[0] = stack_top_p[-1];
-          stack_top_p[-1] = ECMA_VALUE_UNDEFINED;
-          stack_top_p++;
-          continue;
-        }
         case VM_OC_IDENT_REFERENCE:
         {
           uint16_t literal_index;

jerry-core/vm/vm.h

@@ -125,7 +125,6 @@ typedef enum
 
   VM_OC_SET_GETTER,              /**< set getter */
   VM_OC_SET_SETTER,              /**< set setter */
-  VM_OC_PUSH_UNDEFINED_BASE,     /**< push undefined base */
   VM_OC_PUSH_ARRAY,              /**< push array */
   VM_OC_PUSH_ELISON,             /**< push elison */
   VM_OC_APPEND_ARRAY,            /**< append array */