Fix IfBuilder::Deopt to clear the current block.

R=jkummerow@chromium.org
BUG=chromium:243868
TEST=mjsunit/regress/regress-crbug-243868

Review URL: https://codereview.chromium.org/16155003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14854 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/hydrogen.cc

@@ -812,6 +812,7 @@ void HGraphBuilder::IfBuilder::Else() {
 void HGraphBuilder::IfBuilder::Deopt() {
   HBasicBlock* block = builder_->current_block();
   block->FinishExitWithDeoptimization(HDeoptimize::kUseAll);
+  builder_->set_current_block(NULL);
   if (did_else_) {
     first_false_block_ = NULL;
   } else {
@@ -7195,6 +7196,7 @@ HValue* HOptimizedGraphBuilder::HandlePolymorphicElementAccess(
 
   // If only one map is left after transitioning, handle this case
   // monomorphically.
+  ASSERT(num_untransitionable_maps >= 1);
   if (num_untransitionable_maps == 1) {
     HInstruction* instr = NULL;
     if (untransitionable_map->has_slow_elements_kind()) {

test/mjsunit/regress/regress-crbug-243868.js

+// Copyright 2013 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
+
+var non_const_true = true;
+
+function f(o) {
+  return (non_const_true && (o.val == null || false));
+}
+
+// Create an object with a constant function in another realm.
+var realm = Realm.create();
+var realmObject = Realm.eval(realm, "function g() {}; var o = { val:g }; o;")
+
+// Make the CompareNil IC in the function monomorphic.
+assertFalse(f(realmObject));
+assertFalse(f(realmObject));
+
+// Optimize the function containing the CompareNil IC.
+%OptimizeFunctionOnNextCall(f);
+assertFalse(f(realmObject));