Support double allocations when folding allocation.

test/mjsunit/allocation-folding.js

 // Copyright 2013 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 --nouse-osr
+// Flags: --allow-natives-syntax --nouse-osr --expose-gc
+
+// Test loop barrier when folding allocations.
+
 function f() {
   var elem1 = [1,2,3];
   for (var i=0; i < 100000; i++) {
     var bar = [1];
   }
   var elem2 = [1,2,3];
   return elem2;
 }
 
 f(); f(); f();
 %OptimizeFunctionOnNextCall(f);
 var result = f();
 
-for (var i=0; i < 100000; i++) {
-  var bar = [1];
+gc();
+
+assertEquals(result[2], 3);
+
+// Test allocation folding of doubles.
+
+function doubles() {
+  var elem1 = [1.1, 1.2];
+  var elem2 = [2.1, 2.2];
+  return elem2;
 }
 
-assertEquals(result[2], 3);
+doubles(); doubles(); doubles();
+%OptimizeFunctionOnNextCall(doubles);
+var result = doubles();
+
+gc();
+
+assertEquals(result[1], 2.2);
+
+// Test allocation folding of doubles into non-doubles.
+
+function doubles_int() {
+  var elem1 = [2, 3];
+  var elem2 = [2.1, 3.1];
+  return elem2;
+}
+
+doubles_int(); doubles_int(); doubles_int();
+%OptimizeFunctionOnNextCall(doubles_int);
+var result = doubles_int();
+
+gc();
+
+assertEquals(result[1], 3.1);