Disable loop invariant code motion on deoptimized functions.

runtime/vm/compiler.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/compiler.h"
 
 #include "vm/assembler.h"
 #include "vm/ast_printer.h"
 #include "vm/code_generator.h"
 #include "vm/code_patcher.h"
@@ skipping 195 matching lines @@
         if (FLAG_constant_propagation ||
             FLAG_common_subexpression_elimination) {
           flow_graph->ComputeUseLists();
         }
         if (FLAG_constant_propagation) {
           ConstantPropagator::Optimize(flow_graph);
         }
         if (FLAG_common_subexpression_elimination) {
           DominatorBasedCSE::Optimize(flow_graph);
         }
-        if (FLAG_loop_invariant_code_motion) {
+        if (FLAG_loop_invariant_code_motion &&
+            parsed_function.function().deoptimization_counter() == 0) {

[Florian Schneider, 2012/09/24 11:08:50]

Since there could be other deoptimizations than those caused by code motion, I'd
rather write

parsed_function.function().deoptimization_counter() ==
FLAG_deoptimization_counter_threshold - 1 

to only disable it on the last re-compilation.

           LICM::Optimize(flow_graph);
         }
 
         if (FLAG_range_analysis) {
           // We have to perform range analysis after LICM because it
           // optimistically moves CheckSmi through phis into loop preheaders
           // making some phis smi.
           flow_graph->ComputeUseLists();
           optimizer.InferSmiRanges();
         }
@@ skipping 355 matching lines @@
     result = isolate->object_store()->sticky_error();
     isolate->object_store()->clear_sticky_error();
     isolate->set_long_jump_base(base);
     return result.raw();
   }
   UNREACHABLE();
   return Object::null();
 }
 
 }  // namespace dart