Disable hoisting CheckClass due to excessive deoptimization.

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/block_scheduler.h"
@@ skipping 30 matching lines @@
 DEFINE_FLAG(bool, constant_propagation, true,
     "Do conditional constant propagation/unreachable code elimination.");
 DEFINE_FLAG(bool, common_subexpression_elimination, true,
     "Do common subexpression elimination.");
 DEFINE_FLAG(bool, loop_invariant_code_motion, true,
     "Do loop invariant code motion.");
 DEFINE_FLAG(bool, allocation_sinking, true,
     "Attempt to sink temporary allocations to side exits");
 DEFINE_FLAG(int, deoptimization_counter_threshold, 16,
     "How many times we allow deoptimization before we disallow optimization.");
-DEFINE_FLAG(int, deoptimization_counter_licm_threshold, 8,
-    "How many times we allow deoptimization before we disable LICM.");
 DEFINE_FLAG(bool, print_flow_graph, false, "Print the IR flow graph.");
 DEFINE_FLAG(bool, print_flow_graph_optimized, false,
             "Print the IR flow graph when optimizing.");
 DEFINE_FLAG(bool, range_analysis, true, "Enable range analysis");
 DEFINE_FLAG(bool, reorder_basic_blocks, true, "Enable basic-block reordering.");
 DEFINE_FLAG(bool, use_inlining, true, "Enable call-site inlining");
 DEFINE_FLAG(bool, verify_compiler, false,
     "Enable compiler verification assertions");
 DECLARE_FLAG(bool, trace_failed_optimization_attempts);
 
@@ skipping 372 matching lines @@
             DEBUG_ASSERT(flow_graph->VerifyUseLists());
           }
         }
 
         // Optimize (a << b) & c patterns, merge operations.
         // Run after CSE in order to have more opportunity to merge
         // instructions that have same inputs.
         optimizer.TryOptimizePatterns();
         DEBUG_ASSERT(flow_graph->VerifyUseLists());
 
-        if (FLAG_loop_invariant_code_motion &&
-            (function.deoptimization_counter() <
-             FLAG_deoptimization_counter_licm_threshold)) {
+        if (FLAG_loop_invariant_code_motion) {
           LICM licm(flow_graph);
           licm.Optimize();
           DEBUG_ASSERT(flow_graph->VerifyUseLists());
         }
         flow_graph->RemoveRedefinitions();
 
         if (FLAG_range_analysis) {
           // Propagate types after store-load-forwarding. Some phis may have
           // become smi phis that can be processed by range analysis.
           FlowGraphTypePropagator::Propagate(flow_graph);
@@ skipping 488 matching lines @@
     const Object& result =
       Object::Handle(isolate->object_store()->sticky_error());
     isolate->object_store()->clear_sticky_error();
     return result.raw();
   }
   UNREACHABLE();
   return Object::null();
 }
 
 }  // namespace dart