When merging a frame to an expected on at block entry, the static type

of elements is set to a safe lower bound.  Move the setting of the
static type out of VirtualFrame::MergeTo (which is not necessarily run
for all frames) and into VirtualFrame::PrepareMergeTo (which is).
Review URL: http://codereview.chromium.org/92009

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1767 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/virtual-frame-ia32.cc

@@ -191,7 +191,6 @@ void VirtualFrame::MergeTo(VirtualFrame* expected) {
     if (elements_[i].is_copy()) {
       elements_[elements_[i].index()].set_copied();
     }
-    elements_[i].set_static_type(target.static_type());
   }
 
   // Adjust the stack pointer downward if necessary.

src/virtual-frame.cc

@@ -297,6 +297,10 @@ void VirtualFrame::PrepareMergeTo(VirtualFrame* expected) {
     if (elements_[i].is_copy()) {
       elements_[elements_[i].index()].set_copied();
     }
+
+    // No code needs to be generated to change the static type of an
+    // element.
+    elements_[i].set_static_type(target.static_type());
   }
 }
 

test/mjsunit/regress/regress-318.js

+// Copyright 2009 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.
+
+// Should not raise an exception.
+
+function test(value) {
+  if (typeof(value) == 'boolean') value = value + '';
+  if (typeof(value) == 'number') value = value + '';
+}
+
+assertDoesNotThrow(test(0));