Cache String.split not found results as well

src/runtime/runtime-regexp.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/conversions-inl.h"
 #include "src/isolate-inl.h"
 #include "src/messages.h"
@@ skipping 720 matching lines @@
 
   // Create JSArray of substrings separated by separator.
   int part_count = indices.length();
 
   Handle<JSArray> result = isolate->factory()->NewJSArray(part_count);
   JSObject::EnsureCanContainHeapObjectElements(result);
   result->set_length(Smi::FromInt(part_count));
 
   DCHECK(result->HasFastObjectElements());
 
+  Handle<FixedArray> elements(FixedArray::cast(result->elements()));
+
   if (part_count == 1 && indices.at(0) == subject_length) {
-    FixedArray::cast(result->elements())->set(0, *subject);
-    return *result;
-  }
-
-  Handle<FixedArray> elements(FixedArray::cast(result->elements()));
-  int part_start = 0;
-  for (int i = 0; i < part_count; i++) {
-    HandleScope local_loop_handle(isolate);
-    int part_end = indices.at(i);
-    Handle<String> substring =
-        isolate->factory()->NewProperSubString(subject, part_start, part_end);
-    elements->set(i, *substring);
-    part_start = part_end + pattern_length;
+    elements->set(0, *subject);
+  } else {
+    int part_start = 0;
+    for (int i = 0; i < part_count; i++) {
+      HandleScope local_loop_handle(isolate);
+      int part_end = indices.at(i);
+      Handle<String> substring =
+          isolate->factory()->NewProperSubString(subject, part_start, part_end);
+      elements->set(i, *substring);
+      part_start = part_end + pattern_length;
+    }
   }
 
   if (limit == 0xffffffffu) {
     if (result->HasFastObjectElements()) {
       RegExpResultsCache::Enter(isolate, subject, pattern, elements,
                                 RegExpResultsCache::STRING_SPLIT_SUBSTRINGS);
     }
   }
 
   return *result;
@@ skipping 414 matching lines @@
 
 
 RUNTIME_FUNCTION(Runtime_IsRegExp) {
   SealHandleScope shs(isolate);
   DCHECK(args.length() == 1);
   CONVERT_ARG_CHECKED(Object, obj, 0);
   return isolate->heap()->ToBoolean(obj->IsJSRegExp());
 }
 }  // namespace internal
 }  // namespace v8