Make MathFloorOfDiv optimization trigger more often

src/hydrogen.cc

 // Copyright 2012 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 2992 matching lines @@
         // (Before each HEnterInlined, there is a non-foldable HSimulate
         // anyway, so we get the barrier in the other direction for free.)
         // Simply remove all accumulated simulates without merging.  This
         // is safe because simulates after instructions with side effects
         // are never added to the merge list.
         while (!mergelist.is_empty()) {
           mergelist.RemoveLast()->DeleteAndReplaceWith(NULL);
         }
         continue;
       }
+      if (current->IsReturn()) {
+        // Drop mergeable simulates in the list. This is safe because
+        // simulates after instructions with side effects are never added
+        // to the merge list.
+        while (!mergelist.is_empty()) {
+          mergelist.RemoveLast()->DeleteAndReplaceWith(NULL);
+        }
+        continue;
+      }
       // Skip the non-simulates and the first simulate.
       if (!current->IsSimulate()) continue;
       if (first) {
         first = false;
         continue;
       }
       HSimulate* current_simulate = HSimulate::cast(current);
       if ((current_simulate->previous()->HasObservableSideEffects() &&
            !current_simulate->next()->IsSimulate()) ||
           !current_simulate->is_candidate_for_removal()) {
@@ skipping 8588 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify(false);  // No full verify.
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal