Take loop side-effects into account when collecting side-effects on the path between two blocks.

src/hydrogen.cc

 // 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
@@ skipping 1485 matching lines @@
 
 int HGlobalValueNumberer::CollectSideEffectsOnPathsToDominatedBlock(
     HBasicBlock* dominator, HBasicBlock* dominated) {
   int side_effects = 0;
   for (int i = 0; i < dominated->predecessors()->length(); ++i) {
     HBasicBlock* block = dominated->predecessors()->at(i);
     if (dominator->block_id() < block->block_id() &&
         block->block_id() < dominated->block_id() &&
         visited_on_paths_.Add(block->block_id())) {
       side_effects |= block_side_effects_[block->block_id()];
+      if (block->IsLoopHeader()) {
+        side_effects |= loop_side_effects_[block->block_id()];
+      }
       side_effects |= CollectSideEffectsOnPathsToDominatedBlock(
           dominator, block);
     }
   }
   return side_effects;
 }
 
 
 void HGlobalValueNumberer::AnalyzeBlock(HBasicBlock* block, HValueMap* map) {
   TraceGVN("Analyzing block B%d%s\n",
@@ skipping 5494 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify(false);  // No full verify.
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal