Reapply: Inline fast cases in string keyed load IC.

test/mjsunit/string-index.js

 // Copyright 2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 17 matching lines @@
 /**
  * @fileoverview Test indexing on strings with [].
  */
 
 var foo = "Foo";
 assertEquals("Foo", foo);
 assertEquals("F", foo[0]);
 assertEquals("o", foo[1]);
 assertEquals("o", foo[2]);
 
+// Test string keyed load IC.
+for (var i = 0; i < 10; i++) {
+  assertEquals("F", foo[0]);
+  assertEquals("o", foo[1]);
+  assertEquals("o", foo[2]);
+  assertEquals("F", (foo[0] + "BarBazQuuxFooBarQuux")[0]);
+}
+
 assertEquals("F", foo["0" + ""], "string index");
 assertEquals("o", foo["1"], "string index");
 assertEquals("o", foo["2"], "string index");
 
 assertEquals("undefined", typeof(foo[3]), "out of range");
 // SpiderMonkey 1.5 fails this next one.  So does FF 2.0.6.
 assertEquals("undefined", typeof(foo[-1]), "known failure in SpiderMonkey 1.5");
 assertEquals("undefined", typeof(foo[-2]), "negative index");
 
 foo[0] = "f";
@@ skipping 123 matching lines @@
 var foo = ['a12', ['a', 2, 'c'], 'a31', 42];
 var results = [1, 2, 3, NaN];
 for (var i = 0; i < 200; ++i) {
   var index = Math.floor(i / 50);
   var receiver = foo[index];
   var expected = results[index];
   var actual = +(receiver[1]);
   assertEquals(expected, actual);
 }
 
-var keys = [0, '1', 2, 3.0];
-var str = 'abcd', arr = ['a', 'b', 'c', 'd'];
-for (var i = 0; i < 200; ++i) {
+var keys = [0, '1', 2, 3.0, -1, 10];
+var str = 'abcd', arr = ['a', 'b', 'c', 'd', undefined, undefined];
+for (var i = 0; i < 300; ++i) {
   var index = Math.floor(i / 50);
   var key = keys[index];
   var expected = arr[index];
   var actual = str[key];
   assertEquals(expected, actual);
 }