Simplify and improve optimization of is-tests in the precompiler.

runtime/vm/flow_graph_inliner.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/flow_graph_inliner.h"
 
 #include "vm/aot_optimizer.h"
 #include "vm/block_scheduler.h"
 #include "vm/branch_optimizer.h"
 #include "vm/compiler.h"
@@ skipping 845 matching lines @@
             optimizer.ApplyICData();
             DEBUG_ASSERT(callee_graph->VerifyUseLists());
 
             // Optimize (a << b) & c patterns, merge instructions. Must occur
             // before 'SelectRepresentations' which inserts conversion nodes.
             optimizer.TryOptimizePatterns();
             DEBUG_ASSERT(callee_graph->VerifyUseLists());
           }
         }
 
-        if (FLAG_support_il_printer && FLAG_trace_inlining &&
+        if (FLAG_support_il_printer && trace_inlining() &&
             (FLAG_print_flow_graph || FLAG_print_flow_graph_optimized)) {
           THR_Print("Callee graph for inlining %s\n",
                     function.ToFullyQualifiedCString());
           FlowGraphPrinter printer(*callee_graph);
           printer.PrintBlocks();
         }
 
         // Collect information about the call site and caller graph.
         // TODO(zerny): Do this after CP and dead code elimination.
         intptr_t constants_count = 0;
@@ skipping 2256 matching lines @@
       return InlineDoubleOp(flow_graph, Token::kMUL, call, entry, last);
     case MethodRecognizer::kDoubleDiv:
       return InlineDoubleOp(flow_graph, Token::kDIV, call, entry, last);
     default:
       return false;
   }
 }
 
 
 }  // namespace dart