- Correctly handle negative constant indices when

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/flow_graph_builder.h"
 #include "vm/flow_graph_compiler.h"
@@ skipping 673 matching lines @@
                                               Definition** array,
                                               Definition** index) {
   // Insert class check and index smi checks and attach a copy of the
   // original environment because the operation can still deoptimize.
   AddReceiverCheck(call);
   InsertBefore(call,
                new CheckSmiInstr(new Value(*index), call->deopt_id()),
                call->env(),
                Definition::kEffect);
 
-  // If both index and array are constants, then do a compile-time check.
-  // TODO(srdjan): Remove once constant propagation handles bounds checks.
-  bool skip_check = false;
-  if ((*array)->IsConstant() && (*index)->IsConstant()) {
-    const ImmutableArray& constant_array =
-        ImmutableArray::Cast((*array)->AsConstant()->value());
-    const Object& constant_index = (*index)->AsConstant()->value();
-      skip_check = constant_index.IsSmi() &&
-          (Smi::Cast(constant_index).Value() < constant_array.Length());
-  }
-  if (!skip_check) {
-    // Insert array length load and bounds check.
-    const bool is_immutable =
-        CheckArrayBoundInstr::IsFixedLengthArrayType(class_id);
-    LoadFieldInstr* length =
-        new LoadFieldInstr(new Value(*array),
-                           CheckArrayBoundInstr::LengthOffsetFor(class_id),
-                           Type::ZoneHandle(Type::SmiType()),
-                           is_immutable);
-    length->set_result_cid(kSmiCid);
-    length->set_recognized_kind(
-        LoadFieldInstr::RecognizedKindFromArrayCid(class_id));
-    InsertBefore(call, length, NULL, Definition::kValue);
+  // Insert array length load and bounds check.
+  const bool is_immutable =
+      CheckArrayBoundInstr::IsFixedLengthArrayType(class_id);
+  LoadFieldInstr* length =
+      new LoadFieldInstr(new Value(*array),
+                         CheckArrayBoundInstr::LengthOffsetFor(class_id),
+                         Type::ZoneHandle(Type::SmiType()),
+                         is_immutable);
+  length->set_result_cid(kSmiCid);
+  length->set_recognized_kind(
+      LoadFieldInstr::RecognizedKindFromArrayCid(class_id));
+  InsertBefore(call, length, NULL, Definition::kValue);
+  InsertBefore(call,
+               new CheckArrayBoundInstr(new Value(length),
+                                        new Value(*index),
+                                        class_id,
+                                        call),
+               call->env(),
+               Definition::kEffect);
 
-    InsertBefore(call,
-                 new CheckArrayBoundInstr(new Value(length),
-                                          new Value(*index),
-                                          class_id,
-                                          call),
-                 call->env(),
-                 Definition::kEffect);
-  }
   if (class_id == kGrowableObjectArrayCid) {
     // Insert data elements load.
     LoadFieldInstr* elements =
         new LoadFieldInstr(new Value(*array),
                            GrowableObjectArray::data_offset(),
                            Type::ZoneHandle(Type::DynamicType()));
     elements->set_result_cid(kArrayCid);
     InsertBefore(call, elements, NULL, Definition::kValue);
     *array = elements;
     return kArrayCid;
@@ skipping 5770 matching lines @@
 
   // Insert materializations at environment uses.
   const Class& cls = Class::Handle(alloc->constructor().Owner());
   for (intptr_t i = 0; i < exits.length(); i++) {
     CreateMaterializationAt(exits[i], alloc, cls, *fields);
   }
 }
 
 
 }  // namespace dart