Add DoubleToSmi optimistically, preventing boxing/unboxing of doubles and propagate smi-nessof the …

runtime/vm/flow_graph_optimizer.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/flow_graph_optimizer.h"
 
 #include "vm/bit_vector.h"
 #include "vm/cha.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/flow_graph_compiler.h"
@@ skipping 1185 matching lines @@
     SmiToDoubleInstr* s2d_instr = new SmiToDoubleInstr(call);
     call->ReplaceWith(s2d_instr, current_iterator());
     // Pushed arguments are not removed because SmiToDouble is implemented
     // as a call.
     return true;
   }
 
   if ((recognized_kind == MethodRecognizer::kDoubleToInteger) &&
       (class_ids[0] == kDoubleCid)) {
     AddCheckClass(call, call->ArgumentAt(0)->value()->Copy());
-    DoubleToIntegerInstr* d2int_instr =
-        new DoubleToIntegerInstr(call->ArgumentAt(0)->value(), call);
-    call->ReplaceWith(d2int_instr, current_iterator());
+    ASSERT(call->HasICData());
+    const ICData& ic_data = *call->ic_data();
+    Definition* d2i_instr = NULL;
+    if (ic_data.deopt_reason() == kDeoptDoubleToSmi) {
+      // Do not repeatedly deoptimize because result didn't fit into Smi.
+      d2i_instr = new DoubleToIntegerInstr(call->ArgumentAt(0)->value(), call);
+    } else {
+      // Optimistically assume result fits into Smi.
+      d2i_instr = new DoubleToSmiInstr(call->ArgumentAt(0)->value(), call);
+    }
+    call->ReplaceWith(d2i_instr, current_iterator());
     RemovePushArguments(call);
     return true;
   }
 
   return false;
 }
 
 
 // Tries to optimize instance call by replacing it with a faster instruction
 // (e.g, binary op, field load, ..).
@@ skipping 2821 matching lines @@
   SetValue(instr, non_constant_);
 }
 
 
 void ConstantPropagator::VisitDoubleToInteger(DoubleToIntegerInstr* instr) {
   // TODO(kmillikin): Handle conversion.
   SetValue(instr, non_constant_);
 }
 
 
+void ConstantPropagator::VisitDoubleToSmi(DoubleToSmiInstr* instr) {
+  // TODO(kmillikin): Handle conversion.
+  SetValue(instr, non_constant_);
+}
+
+
 void ConstantPropagator::VisitConstant(ConstantInstr* instr) {
   SetValue(instr, instr->value());
 }
 
 
 void ConstantPropagator::VisitConstraint(ConstraintInstr* instr) {
   // Should not be used outside of range analysis.
   UNREACHABLE();
 }
 
@@ skipping 209 matching lines @@
 
   if (FLAG_trace_constant_propagation) {
     OS::Print("\n==== After constant propagation ====\n");
     FlowGraphPrinter printer(*graph_);
     printer.PrintBlocks();
   }
 }
 
 
 }  // namespace dart