Fix a small bug in trace printing for discovered loops.

runtime/vm/flow_graph.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/flow_graph.h"
 
 #include "vm/bit_vector.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/intermediate_language.h"
 #include "vm/longjump.h"
@@ skipping 937 matching lines @@
         instr_it.RemoveCurrentFromGraph();
       }
     }
   }
 }
 
 
 // Find the natural loop for the back edge m->n and attach loop information
 // to block n (loop header). The algorithm is described in "Advanced Compiler
 // Design & Implementation" (Muchnick) p192.
-static void FindLoop(BlockEntryInstr* m,
-                     BlockEntryInstr* n,
-                     intptr_t num_blocks) {
+void FlowGraph::FindLoop(BlockEntryInstr* m, BlockEntryInstr* n) {
   GrowableArray<BlockEntryInstr*> stack;
-  BitVector* loop = new BitVector(num_blocks);
+  BitVector* loop = new BitVector(preorder_.length());
 
   loop->Add(n->preorder_number());
   if (n != m) {
     loop->Add(m->preorder_number());
     stack.Add(m);
   }
 
   while (!stack.is_empty()) {
     BlockEntryInstr* p = stack.RemoveLast();
     for (intptr_t i = 0; i < p->PredecessorCount(); ++i) {
       BlockEntryInstr* q = p->PredecessorAt(i);
       if (!loop->Contains(q->preorder_number())) {
         loop->Add(q->preorder_number());
         stack.Add(q);
       }
     }
   }
   n->set_loop_info(loop);
   if (FLAG_trace_optimization) {
     for (BitVector::Iterator it(loop); !it.Done(); it.Advance()) {
-      OS::Print("  B%"Pd"\n", it.Current());
+      OS::Print("  B%"Pd"\n", preorder_[it.Current()]->block_id());
     }
   }
 }
 
 
 ZoneGrowableArray<BlockEntryInstr*>* FlowGraph::ComputeLoops() {
   ZoneGrowableArray<BlockEntryInstr*>* loop_headers =
       new ZoneGrowableArray<BlockEntryInstr*>();
 
   for (BlockIterator it = postorder_iterator();
        !it.Done();
        it.Advance()) {
     BlockEntryInstr* block = it.Current();
     for (intptr_t i = 0; i < block->PredecessorCount(); ++i) {
       BlockEntryInstr* pred = block->PredecessorAt(i);
       if (block->Dominates(pred)) {
         if (FLAG_trace_optimization) {
           OS::Print("Back edge B%"Pd" -> B%"Pd"\n", pred->block_id(),
                     block->block_id());
         }
-        FindLoop(pred, block, preorder_.length());
+        FindLoop(pred, block);
         loop_headers->Add(block);
       }
     }
   }
 
   return loop_headers;
 }
 
 
 void FlowGraph::Bailout(const char* reason) const {
@@ skipping 125 matching lines @@
 }
 
 
 bool BlockEffects::IsSideEffectFreePath(BlockEntryInstr* from,
                                         BlockEntryInstr* to) const {
   return available_at_[to->postorder_number()]->Contains(
       from->postorder_number());
 }
 
 }  // namespace dart