Emit mementos in crankshaft.

test/mjsunit/array-constructor-feedback.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
@@ skipping 172 matching lines @@
     a = bar();
     bar();
     %OptimizeFunctionOnNextCall(bar);
     b = bar();
     // This only makes sense to test if we allow crankshafting
     if (4 != %GetOptimizationStatus(bar)) {
       assertOptimized(bar);
       %DebugPrint(3);
       b[0] = 3.5;
       c = bar();
+      // This assert should be relaxed as we may continue emitting mementos for
+      // pretenuring purposes in crankshaft if we don't have enough samples yet.
       assertKind(elements_kind.fast_smi_only, c);
       assertOptimized(bar);
     }
   })();
 
 
   // Test: create arrays in two contexts, verifying that the correct
   // map for Array in that context will be used.
   (function() {
     function bar() { return new Array(); }
@@ skipping 29 matching lines @@
     assertTrue(isHoley(a));
     a = bar(0);
     assertOptimized(bar);
     // Crankshafted functions don't use mementos, so feedback still
     // indicates a packed array is desired. (unless --nocrankshaft is in use).
     if (4 != %GetOptimizationStatus(bar)) {
       assertFalse(isHoley(a));
     }
   })();
 }