Improve load forwarding:

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/bit_vector.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_allocator.h"
 #include "vm/flow_graph_builder.h"
@@ skipping 1178 matching lines @@
   return HasUses() ? this : NULL;
 }
 
 
 Definition* LoadFieldInstr::Canonicalize(FlowGraphOptimizer* optimizer) {
   if (!IsImmutableLengthLoad()) return this;
 
   // For fixed length arrays if the array is the result of a known constructor
   // call we can replace the length load with the length argument passed to
   // the constructor.
-  StaticCallInstr* call = value()->definition()->AsStaticCall();
+  StaticCallInstr* call = instance()->definition()->AsStaticCall();
   if ((call != NULL) &&
       call->is_known_list_constructor() &&
       IsFixedLengthArrayCid(call->Type()->ToCid())) {
     return call->ArgumentAt(1);
   }
   return this;
 }
 
 
 Definition* AssertBooleanInstr::Canonicalize(FlowGraphOptimizer* optimizer) {
@@ skipping 28 matching lines @@
     ConstantInstr* null_constant = new ConstantInstr(Object::ZoneHandle());
     // It is ok to insert instructions before the current during
     // forward iteration.
     optimizer->InsertBefore(this, null_constant, NULL, Definition::kValue);
     instantiator_type_arguments()->BindTo(null_constant);
   }
   return this;
 }
 
 
+Definition* BoxDoubleInstr::Canonicalize(FlowGraphOptimizer* optimizer) {
+  if (input_use_list() == NULL) {
+    // Environments can accomodate any representation. No need to box.
+    return value()->definition();
+  }
+
+  // Fold away BoxDouble(UnboxDouble(v)) if value is known to be double.
+  UnboxDoubleInstr* defn = value()->definition()->AsUnboxDouble();
+  if ((defn != NULL) && (defn->value()->Type()->ToCid() == kDoubleCid)) {
+    return defn->value()->definition();
+  }
+
+  return this;
+}
+
+
+Definition* UnboxDoubleInstr::Canonicalize(FlowGraphOptimizer* optimizer) {
+  // Fold away UnboxDouble(BoxDouble(v)).
+  BoxDoubleInstr* defn = value()->definition()->AsBoxDouble();
+  return (defn != NULL) ? defn->value()->definition() : this;
+}
+
+
 Instruction* BranchInstr::Canonicalize(FlowGraphOptimizer* optimizer) {
   // Only handle strict-compares.
   if (comparison()->IsStrictCompare()) {
     Definition* replacement = comparison()->Canonicalize(optimizer);
     if ((replacement == comparison()) || (replacement == NULL)) {
       return this;
     }
     ComparisonInstr* comp = replacement->AsComparison();
     if ((comp == NULL) || comp->CanDeoptimize()) {
       return this;
@@ skipping 1135 matching lines @@
     default:
       UNREACHABLE();
   }
   return kPowRuntimeEntry;
 }
 
 
 #undef __
 
 }  // namespace dart