From bc4d7878e6ac17e3df184640c352ca5489095d5c Mon Sep 17 00:00:00 2001
From: "ulan@chromium.org"
 <ulan@chromium.org@ce2b1a6d-e550-0410-aec6-3dcde31c8c00>
Date: Tue, 23 Apr 2013 15:28:44 +0000
Subject: [PATCH] Do not emit Simulates in HandlePolymorphicElementAccess.

BUG=v8:2653
R=jkummerow@chromium.org
TEST=mjsunit/regress/regress-2653.js

Review URL: https://chromiumcodereview.appspot.com/14081025

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14396 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
---
 src/hydrogen.cc                      |  9 ++++---
 test/mjsunit/regress/regress-2653.js | 47 ++++++++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+), 3 deletions(-)
 create mode 100644 test/mjsunit/regress/regress-2653.js

diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index f21fd42..20e1d0d 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -7690,10 +7690,12 @@ HValue* HOptimizedGraphBuilder::HandlePolymorphicElementAccess(
         }
 
         *has_side_effects |= access->HasObservableSideEffects();
+        // The caller will use has_side_effects and add correct Simulate.
+        access->SetFlag(HValue::kHasNoObservableSideEffects);
         if (position != -1) {
           access->set_position(position);
         }
-        if_jsarray->Goto(join);
+        if_jsarray->GotoNoSimulate(join);
 
         set_current_block(if_fastobject);
         length = AddInstruction(new(zone()) HFixedArrayBaseLength(elements));
@@ -7713,18 +7715,19 @@ HValue* HOptimizedGraphBuilder::HandlePolymorphicElementAccess(
             elements_kind_branch, elements_kind, is_store));
       }
       *has_side_effects |= access->HasObservableSideEffects();
+      // The caller will use has_side_effects and add correct Simulate.
+      access->SetFlag(HValue::kHasNoObservableSideEffects);
       if (position != RelocInfo::kNoPosition) access->set_position(position);
       if (!is_store) {
         Push(access);
       }
-      current_block()->Goto(join);
+      current_block()->GotoNoSimulate(join);
       set_current_block(if_false);
     }
   }
 
   // Deopt if none of the cases matched.
   current_block()->FinishExitWithDeoptimization(HDeoptimize::kNoUses);
-  join->SetJoinId(ast_id);
   set_current_block(join);
   return is_store ? NULL : Pop();
 }
diff --git a/test/mjsunit/regress/regress-2653.js b/test/mjsunit/regress/regress-2653.js
new file mode 100644
index 0000000..eb0c631
--- /dev/null
+++ b/test/mjsunit/regress/regress-2653.js
@@ -0,0 +1,47 @@
+// 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 --deopt_every_n_garbage_collections=1
+
+function foo(a, b) {
+  var l = a.length;
+  var array = new Array(l);
+  for (var k = 0; k < l; k++) {
+    array[k] = 120;
+  }
+  var result = new Array(l);
+  for (var i = 0; i < l; i++) {
+    result[i] = array[i];
+  }
+  return result;
+}
+
+a = "xxxxxxxxxxxxxxxxxxxxxxxxx";
+while (a.length < 100000) a = a + a;
+foo(a, []);
+%OptimizeFunctionOnNextCall(foo)
+foo(a, []);
-- 
2.7.4