Revert r28050 due to crashes with --optimization-counter-threshold=5.

runtime/vm/flow_graph_compiler.cc

 // Copyright (c) 2013, 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/globals.h"  // Needed here to get TARGET_ARCH_XXX.
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/cha.h"
 #include "vm/dart_entry.h"
@@ skipping 152 matching lines @@
 bool FlowGraphCompiler::CanOptimizeFunction() const {
   return CanOptimize() && !parsed_function().function().HasBreakpoint();
 }
 
 
 bool FlowGraphCompiler::CanOSRFunction() const {
   return FLAG_use_osr & CanOptimizeFunction() && !is_optimizing();
 }
 
 
+static bool IsEmptyBlock(BlockEntryInstr* block) {
+  return !block->HasParallelMove() &&
+         block->next()->IsGoto() &&
+         !block->next()->AsGoto()->HasParallelMove();
+}
+
+
 void FlowGraphCompiler::CompactBlock(BlockEntryInstr* block) {
   BlockInfo* block_info = block_info_[block->postorder_number()];
 
   // Break out of cycles in the control flow graph.
   if (block_info->is_marked()) {
     return;
   }
   block_info->mark();
 
-  if (block->IsEmptyBlock()) {
+  if (IsEmptyBlock(block)) {
     // For empty blocks, record a corresponding nonempty target as their
     // jump label.
     BlockEntryInstr* target = block->next()->AsGoto()->successor();
     CompactBlock(target);
     block_info->set_jump_label(GetJumpLabel(target));
   }
 }
 
 
 void FlowGraphCompiler::CompactBlocks() {
@@ skipping 909 matching lines @@
 
   for (int i = 0; i < len; i++) {
     sorted->Add(CidTarget(ic_data.GetReceiverClassIdAt(i),
                           &Function::ZoneHandle(ic_data.GetTargetAt(i)),
                           ic_data.GetCountAt(i)));
   }
   sorted->Sort(HighestCountFirst);
 }
 
 }  // namespace dart