Only invoke reaching definitions if there are >0 variables and >0 definitions...

src/data-flow.cc

 // Copyright 2010 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
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@@ skipping 2043 matching lines @@
   rd_.rd_in()->CopyFrom(new_rd_in);
   // Add the successor to the worklist if not already present.
   if (!successor_->IsMarkedWith(mark)) {
     successor_->MarkWith(mark);
     worklist->Insert(successor_);
   }
 }
 
 
 void ReachingDefinitions::Compute() {
-  if (definitions_->is_empty()) return;
+  ASSERT(!definitions_->is_empty());

[Kevin Millikin (Chromium), 2010/03/12 14:58:16]

I'd leave this check here.

 
   int variable_count = variables_.length();
   int definition_count = definitions_->length();
   int node_count = postorder_->length();
 
   // Step 1: For each variable, identify the set of all its definitions in
   // the body.
   for (int i = 0; i < definition_count; i++) {
     Variable* var = definitions_->at(i)->AssignedVar();
     variables_[IndexFor(var, variable_count)]->Add(i);
@@ skipping 39 matching lines @@
   // all necessary successors to the worklist.
   while (!worklist.is_empty()) {
     Node* node = worklist.Remove();
     node->MarkWith(!mark);
     node->UpdateRDIn(&worklist, mark);
   }
 }
 
 
 } }  // namespace v8::internal