Fix EnsureCanContainElements to properly handle double values.

test/mjsunit/regress/regress-2170.js

+// Copyright 2012 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
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Flags: --allow-natives-syntax
+
+function array_fun() {
+  for (var i = 0; i < 2; i++) {
+    var a = [1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8];
+    var x = new Array();
+    x.fixed$length = true;
+    for (var j = 0; j < a.length; j++) {
+      x.push(a[j]);
+    }
+    for(var j = 0; j < x.length; j++) {
+      if (typeof x[j] != 'number') {
+        throw "foo";
+      }
+      x[j] = x[j];
+    }
+  }
+}
+
+try {
+  for (var i = 0; i < 10; ++i) {
+    array_fun();
+  }
+  %OptimizeFunctionOnNextCall(array_fun);
+  for (var i = 0; i < 10; ++i) {
+    array_fun();
+  }
+} catch (e) {
+  assertUnreachable();
+}
+