Implement local load/store elimination on basic blocks.

test/mjsunit/compiler/load-elimination.js

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-// Flags: --allow-natives-syntax
+// Flags: --allow-natives-syntax --load-elimination
 
-// Test usage of static type information for loads that would otherwise
-// turn into polymorphic or generic loads.
+// Test local load elimination of redundant loads and stores.
 
-// Prepare a highly polymorphic load to be used by all tests.
-Object.prototype.load = function() { return this.property; };
-Object.prototype.load.call({ A:0, property:10 });
-Object.prototype.load.call({ A:0, B:0, property:11 });
-Object.prototype.load.call({ A:0, B:0, C:0, property:12 });
-Object.prototype.load.call({ A:0, B:0, C:0, D:0, property:13 });
-Object.prototype.load.call({ A:0, B:0, C:0, D:0, E:0, property:14 });
-Object.prototype.load.call({ A:0, B:0, C:0, D:0, E:0, F:0, property:15 });
+function B(x, y) {
+  this.x = x;
+  this.y = y;
+  return this;
+}
 
-// Test for object literals.
-(function() {
-  function f(x) {
-    var object = { property:x };
-    return object.load();
-  }
+function test_load() {
+  var a = new B(1, 2);
+  return a.x + a.x + a.x + a.x;
+}
 
-  assertSame(1, f(1));
-  assertSame(2, f(2));
+function test_store_load() {
+  var a = new B(1, 2);
+  a.x = 4;
+  var f = a.x;
+  a.x = 5;
+  var g = a.x;
+  a.x = 6;
+  var h = a.x;
+  a.x = 7;
+  return f + g + h + a.x;
+}
+
+function test_nonaliasing_store1() {
+  var a = new B(2, 3), b = new B(3, 4);
+  b.x = 4;
+  var f = a.x;
+  b.x = 5;
+  var g = a.x;
+  b.x = 6;
+  var h = a.x;
+  b.x = 7;
+  return f + g + h + a.x;
+}
+
+function killall() {
+  try { } catch(e) { }
+}
+
+%NeverOptimizeFunction(killall);
+
+function test_store_load_kill() {
+  var a = new B(1, 2);
+  a.x = 4;
+  var f = a.x;
+  a.x = 5;
+  var g = a.x;
+  killall();
+  a.x = 6;
+  var h = a.x;
+  a.x = 7;
+  return f + g + h + a.x;
+}
+
+function test_store_store() {
+  var a = new B(6, 7);
+  a.x = 7;
+  a.x = 7;
+  a.x = 7;
+  a.x = 7;
+  return a.x;
+}
+
+function test(x, f) {
+  assertEquals(x, f());
+  assertEquals(x, f());
   %OptimizeFunctionOnNextCall(f);
-  assertSame(3, f(3));
-})();
+  assertEquals(x, f());
+}
 
-// Test for inlined constructors.
-(function() {
-  function c(x) {
-    this.property = x;
-  }
-  function f(x) {
-    var object = new c(x);
-    return object.load();
-  }
-
-  assertSame(1, f(1));
-  assertSame(2, f(2));
-  %OptimizeFunctionOnNextCall(f);
-  assertSame(3, f(3));
-})();
+test(4, test_load);
+test(22, test_store_load);
+test(8, test_nonaliasing_store1);
+test(22, test_store_load_kill);
+test(7, test_store_store);