Fix a bug in Lithium environment iteration.

test/mjsunit/regress/regress-1423.js

+// Copyright 2011 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
+
+// Test that the Lithium environment iterator does stop iteration early.
+"use strict";
+
+function f0() {
+  return f1('literal', true);
+}
+
+function f1(x, y) {
+  return f2(x, y);
+}
+
+// Because it's strict, f2 has an environment containing only the constants
+// undefined, 'literal', and false.  Bug 1423 would cause environment
+// iteration to stop early.
+//
+// Bug manifests as UNREACHABLE code (due to an unallocated register) in
+// debug builds.
+function f2(x, y) {
+  if (y) {
+    if (f3(x, 'other-literal')) {
+      return 0;
+    } else {
+      return 1;
+    }
+  } else {
+    return 2;
+  }
+}
+
+function f3(x, y) {
+  return x === y;
+}
+
+for (var i = 0; i < 5; ++i) f0();
+%OptimizeFunctionOnNextCall(f0);
+assertEquals(1, f0());