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      1 // Copyright 2013 the V8 project authors. All rights reserved.
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      3 // modification, are permitted provided that the following conditions are
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      5 //
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      8 //     * Redistributions in binary form must reproduce the above
      9 //       copyright notice, this list of conditions and the following
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     11 //       with the distribution.
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     13 //       contributors may be used to endorse or promote products derived
     14 //       from this software without specific prior written permission.
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     17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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     26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27 
     28 // Flags: --allow-natives-syntax --store-elimination
     29 
     30 // Test local elimination of unobservable stores.
     31 
     32 function B(x, y) {
     33   this.x = x;
     34   this.y = y;
     35   return this;
     36 }
     37 
     38 function test_store_store() {
     39   var a = new B(1, 2);
     40   a.x = 3;  // eliminatable.
     41   a.x = 4;
     42   return a.x;
     43 }
     44 
     45 function test_store_load_store1() {
     46   var a = new B(6, 7);
     47   a.x = 3;  // eliminatable.
     48   var r = a.y;
     49   a.x = 4;
     50   return r;
     51 }
     52 
     53 function test_store_load_store2() {
     54   var a = new B(6, 8);
     55   a.x = 3;  // not eliminatable, unless next load is eliminated.
     56   var r = a.x;
     57   a.x = 4;
     58   return r;
     59 }
     60 
     61 function test_store_call_store() {
     62   var a = new B(2, 9);
     63   a.x = 3;  // not eliminatable.
     64   killall();
     65   a.x = 4;
     66   return a.y;
     67 }
     68 
     69 function test_store_deopt_store() {
     70   var a = new B(2, 1);
     71   a.x = 3;  // not eliminatable (implicit ValueOf following)
     72   var c = a + 2;
     73   a.x = 4;
     74   return a.y;
     75 }
     76 
     77 function killall() {
     78   try { } catch(e) { }
     79 }
     80 
     81 %NeverOptimizeFunction(killall);
     82 
     83 function test(x, f) {
     84   assertEquals(x, f());
     85   assertEquals(x, f());
     86   %OptimizeFunctionOnNextCall(f);
     87   assertEquals(x, f());
     88 }
     89 
     90 test(4, test_store_store);
     91 test(7, test_store_load_store1);
     92 test(3, test_store_load_store2);
     93 test(9, test_store_call_store);
     94 test(1, test_store_deopt_store);
     95