Disable hoisting CheckClass due to excessive deoptimization.

runtime/vm/flow_graph_optimizer.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_optimizer.h"
 
 #include "vm/bit_vector.h"
 #include "vm/cha.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/flow_graph_compiler.h"
 #include "vm/hash_map.h"
 #include "vm/il_printer.h"
 #include "vm/intermediate_language.h"
 #include "vm/object_store.h"
 #include "vm/parser.h"
 #include "vm/resolver.h"
 #include "vm/scopes.h"
 #include "vm/stack_frame.h"
 #include "vm/symbols.h"
 
 namespace dart {
 
 DEFINE_FLAG(bool, array_bounds_check_elimination, true,
     "Eliminate redundant bounds checks.");
+DEFINE_FLAG(int, getter_setter_ratio, 13,
+    "Ratio of getter/setter usage used for double field unboxing heuristics");
 DEFINE_FLAG(bool, load_cse, true, "Use redundant load elimination.");
 DEFINE_FLAG(int, max_polymorphic_checks, 4,
     "Maximum number of polymorphic check, otherwise it is megamorphic.");
 DEFINE_FLAG(int, max_equality_polymorphic_checks, 32,
     "Maximum number of polymorphic checks in equality operator,"
     " otherwise use megamorphic dispatch.");
 DEFINE_FLAG(bool, remove_redundant_phis, true, "Remove redundant phis.");
 DEFINE_FLAG(bool, trace_constant_propagation, false,
     "Print constant propagation and useless code elimination.");
+DEFINE_FLAG(bool, trace_load_optimization, false,
+    "Print live sets for load optimization pass.");
 DEFINE_FLAG(bool, trace_optimization, false, "Print optimization details.");
 DEFINE_FLAG(bool, trace_range_analysis, false, "Trace range analysis progress");
 DEFINE_FLAG(bool, truncating_left_shift, true,
     "Optimize left shift to truncate if possible");
 DEFINE_FLAG(bool, use_cha, true, "Use class hierarchy analysis.");
-DEFINE_FLAG(bool, trace_load_optimization, false,
-    "Print live sets for load optimization pass.");
-DEFINE_FLAG(int, getter_setter_ratio, 13,
-    "Ratio of getter/setter usage used for double field unboxing heuristics");
 DECLARE_FLAG(bool, eliminate_type_checks);
 DECLARE_FLAG(bool, enable_type_checks);
 DECLARE_FLAG(bool, trace_type_check_elimination);
 
 
 static bool ShouldInlineSimd() {
   return FlowGraphCompiler::SupportsUnboxedFloat32x4();
 }
 
 
@@ skipping 4432 matching lines @@
 
 
 LICM::LICM(FlowGraph* flow_graph) : flow_graph_(flow_graph) {
   ASSERT(flow_graph->is_licm_allowed());
 }
 
 
 void LICM::Hoist(ForwardInstructionIterator* it,
                  BlockEntryInstr* pre_header,
                  Instruction* current) {
+  if (current->IsCheckClass()) {
+    current->AsCheckClass()->set_licm_hoisted(true);
+  }
   // TODO(fschneider): Avoid repeated deoptimization when
   // speculatively hoisting checks.
   if (FLAG_trace_optimization) {
     OS::Print("Hoisting instruction %s:%" Pd " from B%" Pd " to B%" Pd "\n",
               current->DebugName(),
               current->GetDeoptId(),
               current->GetBlock()->block_id(),
               pre_header->block_id());
   }
   // Move the instruction out of the loop.
@@ skipping 67 matching lines @@
                                 Instruction* instr) {
   return IsCandidateLoad(instr) &&
       (sets != NULL) &&
       instr->HasPlaceId() &&
       ((*sets)[loop_header_index] != NULL) &&
       (*sets)[loop_header_index]->Contains(instr->place_id());
 }
 
 
 void LICM::Optimize() {
+  if (!flow_graph()->parsed_function().function().
+          allows_hoisting_check_class()) {
+    // Do not hoist any.
+    return;
+  }
+
   const ZoneGrowableArray<BlockEntryInstr*>& loop_headers =
       flow_graph()->loop_headers();
 
   ZoneGrowableArray<BitVector*>* loop_invariant_loads =
       flow_graph()->loop_invariant_loads();
 
   BlockEffects* block_effects = flow_graph()->block_effects();
 
   for (intptr_t i = 0; i < loop_headers.length(); ++i) {
     BlockEntryInstr* header = loop_headers[i];
@@ skipping 3874 matching lines @@
   }
 
   // Insert materializations at environment uses.
   for (intptr_t i = 0; i < exits.length(); i++) {
     CreateMaterializationAt(exits[i], alloc, alloc->cls(), *fields);
   }
 }
 
 
 }  // namespace dart