Simplify generated code for object allocation with type arguments.

runtime/vm/intermediate_language.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/intermediate_language.h"
 
 #include "vm/bigint_operations.h"
 #include "vm/bit_vector.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_allocator.h"
@@ skipping 15 matching lines @@
 
 DEFINE_FLAG(bool, propagate_ic_data, true,
     "Propagate IC data from unoptimized to optimized IC calls.");
 DEFINE_FLAG(bool, unbox_numeric_fields, true,
     "Support unboxed double and float32x4 fields.");
 DECLARE_FLAG(bool, enable_type_checks);
 DECLARE_FLAG(bool, eliminate_type_checks);
 DECLARE_FLAG(bool, trace_optimization);
 DECLARE_FLAG(bool, trace_constant_propagation);
 DECLARE_FLAG(bool, throw_on_javascript_int_overflow);
+DECLARE_FLAG(bool, enable_type_checks);
 
 Definition::Definition()
     : range_(NULL),
       type_(NULL),
       temp_index_(-1),
       ssa_temp_index_(-1),
       input_use_list_(NULL),
       env_use_list_(NULL),
       use_kind_(kValue),  // Phis and parameters rely on this default.
       constant_value_(Object::ZoneHandle(ConstantPropagator::Unknown())) {
@@ skipping 1445 matching lines @@
         value()->Type()->IsAssignableTo(dst_type())) {
       return value()->definition();
     }
     ConstantInstr* null_constant = flow_graph->constant_null();
     instantiator_type_arguments()->BindTo(null_constant);
   }
   return this;
 }
 
 
+Definition* InstantiateTypeArgumentsInstr::Canonicalize(FlowGraph* flow_graph) {
+  return (FLAG_enable_type_checks || HasUses()) ? this : NULL;
+}
+
+
 LocationSummary* DebugStepCheckInstr::MakeLocationSummary(bool opt) const {
   const intptr_t kNumInputs = 0;
   const intptr_t kNumTemps = 0;
   LocationSummary* locs =
       new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kCall);
   return locs;
 }
 
 
 void DebugStepCheckInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
@@ skipping 1633 matching lines @@
     case Token::kTRUNCDIV: return 0;
     case Token::kMOD: return 1;
     default: UNIMPLEMENTED(); return -1;
   }
 }
 
 
 #undef __
 
 }  // namespace dart