Migrated several tests from blink to V8 repository.

test/webkit/dfg-cfg-simplify-phantom-get-local-on-same-block-set-local.js

Index: test/webkit/dfg-cfg-simplify-phantom-get-local-on-same-block-set-local.js
diff --git a/test/webkit/concat-while-having-a-bad-time.js b/test/webkit/dfg-cfg-simplify-phantom-get-local-on-same-block-set-local.js
similarity index 57%
copy from test/webkit/concat-while-having-a-bad-time.js
copy to test/webkit/dfg-cfg-simplify-phantom-get-local-on-same-block-set-local.js
index dfda1e08a0b36194b787a44ee12a9693acd8aeaf..65be965ccfc6c926e93fdaf024c503f5a8e7bf3b 100644
--- a/test/webkit/concat-while-having-a-bad-time.js
+++ b/test/webkit/dfg-cfg-simplify-phantom-get-local-on-same-block-set-local.js
@@ -22,10 +22,42 @@
 // 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 that attempts by the DFG simplification to short-circuit a Phantom to a GetLocal on a variable that is SetLocal'd in the same block, and where the predecessor block(s) make no mention of that variable, do not result in crashes."
 );
 
-Object.defineProperty(Array.prototype, 0, { writable: false });
-shouldBe("[42].concat()", "[42]");
+function baz() {
+    // Do something that prevents inlining.
+    return function() { }
+}
 
+function stuff(z) { }
+
+function foo(x, y) {
+    var a = arguments; // Force arguments to be captured, so that x is captured.
+    baz();
+    var z = x;
+    stuff(z); // Force a Flush, and then a Phantom on the GetLocal of x.
+    return 42;
+}
+
+var o = {
+    g: function(x) { }
+};
+
+function thingy(o) {
+    var p = {};
+    var result;
+    // Trick to delay control flow graph simplification until after the flush of x above gets turned into a phantom.
+    if (o.g)
+        p.f = true;
+    if (p.f) {
+        // Basic block that stores to x in foo(), which is a captured variable, with
+        // the predecessor block making no mention of x.
+        result = foo("hello", 2);
+    }
+    return result;
+}
+
+for (var i = 0; i < 200; ++i)
+    shouldBe("thingy(o)", "42");