Include the loop header block when eliminating stack checks

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 1232 matching lines @@
 void HStackCheckEliminator::Process() {
   // For each loop block walk the dominator tree from the backwards branch to
   // the loop header. If a call instruction is encountered the backwards branch
   // is dominated by a call and the stack check in the backwards branch can be
   // removed.
   for (int i = 0; i < graph_->blocks()->length(); i++) {
     HBasicBlock* block = graph_->blocks()->at(i);
     if (block->IsLoopHeader()) {
       HBasicBlock* back_edge = block->loop_information()->GetLastBackEdge();
       HBasicBlock* dominator = back_edge;
-      bool back_edge_dominated_by_call = false;
-      while (dominator != block && !back_edge_dominated_by_call) {
+      while (true) {
         HInstruction* instr = dominator->first();
-        while (instr != NULL && !back_edge_dominated_by_call) {
+        while (instr != NULL) {
           if (instr->IsCall()) {
             RemoveStackCheck(back_edge);
-            back_edge_dominated_by_call = true;
+            break;
           }
           instr = instr->next();
         }
+
+        // Done when the loop header is processed.
+        if (dominator == block) break;
+
+        // Move up the dominator tree.
         dominator = dominator->dominator();
       }
     }
   }
 }
 
 
 void HStackCheckEliminator::RemoveStackCheck(HBasicBlock* block) {
   HInstruction* instr = block->first();
   while (instr != NULL) {
@@ skipping 5297 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify();
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal