A64: Synchronize with r15545.

test/webkit/dfg-cfg-simplify-eliminate-set-local-type-check-then-typeof.js

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Copyright (C) 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
 //
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 // modification, are permitted provided that the following conditions
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 //     documentation and/or other materials provided with the distribution.
 //
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 // 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 APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
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 // (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
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 // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 description(
-"Tests the behavior of Array.prototype.concat while the array is having a bad time due to one of the elements we are concatenating."
+"Tests what happens when CFG simplification leads to the elimination of a set local that had a type check, and then we do a typeof on the value, which can be constant folded if the type check stays."
 );
 
-Object.defineProperty(Array.prototype, 0, { writable: false });
-shouldBe("[42].concat()", "[42]");
+function foo(o) {
+    var x;
+    if (o.f)
+        x = o.g;
+    else
+        x = o.h;
+    return [typeof x, x - 1];
+}
 
+for (var i = 0; i < 500; ++i) {
+    var o = {f:foo};
+    var expectedFirst;
+    var expectedSecond;
+    if (i < 450) {
+        o.g = i;
+        expectedFirst = "\"number\"";
+        expectedSecond = "" + (i - 1);
+    } else {
+        o.g = "42";
+        expectedFirst = "\"string\"";
+        expectedSecond = "41";
+    }
+    var result = foo(o);
+    shouldBe("result[0]", expectedFirst);
+    shouldBe("result[1]", expectedSecond);
+}