Fix regular and ElementsKind transitions interfering with each other

test/mjsunit/regress/regress-crbug-122271.js

Index: test/mjsunit/regress/regress-crbug-122271.js
diff --git a/test/mjsunit/regress/regress-crbug-122271.js b/test/mjsunit/regress/regress-crbug-122271.js
new file mode 100644
index 0000000000000000000000000000000000000000..3a99a7fa587c881164907fe3db190eb22265c0c2
--- /dev/null
+++ b/test/mjsunit/regress/regress-crbug-122271.js
@@ -0,0 +1,49 @@
+// 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
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY 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 THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (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
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Flags: --allow-natives-syntax
+
+// Tests that ElementsKind transitions and regular transitions don't
+// interfere badly with each other.
+
+var a = [0, 0, 0, 1];
+var b = [0, 0, 0, "one"];
+var c = [0, 0, 0, 1];
+c.foo = "baz";
+
+function foo(array) {
+  array.foo = "bar";
+}
+
+assertTrue(%HasFastSmiOnlyElements(a));
+assertTrue(%HasFastElements(b));
+
+foo(a);
+foo(b);
+
+assertTrue(%HasFastSmiOnlyElements(a));
+assertTrue(%HasFastElements(b));