Fix LoadOptimizer's handling of load/stores with constant indices for TypedData.

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/cpu.h"
 #include "vm/dart_entry.h"
@@ skipping 5069 matching lines @@
 //
 //   - for fields
 //     - *.f, *.@offs - field inside some object;
 //     - X.f, X.@offs - field inside an allocated object X;
 //   - for indexed accesses
 //     - *[*] - non-constant index inside some object;
 //     - *[C] - constant index inside some object;
 //     - X[*] - non-constant index inside an allocated object X;
 //     - X[C] - constant index inside an allocated object X.
 //
+// Constant indexed places are divided into two subcategories:
+//
+//   - Access to homogeneous array-like objects: Array, ImmutableArray,
+//     OneByteString, TwoByteString. These objects can only be accessed
+//     on element by element basis with all elements having the same size.
+//     This means X[C] aliases X[K] if and only if C === K.
+//   - TypedData accesses. TypedData allow to read one of the primitive
+//     data types at the given byte offset. The only guarantee is that byte
+//     offset is always aligned by the data type size. We write these accesses

[Florian Schneider, 2015/01/26 13:30:39]

Do you mean data type size of the underlying array or size of the access?

Because it seems possible to write e.g. an int32 from offset 1 of an
Float32Array: Can you add a test like this? (on ARM it will fail due to
unaligned access due to another issue)

  var x = new Float32List(2);
  var y = x.buffer.asByteData();
  y.setFloat32(0, 1.5);
  y.setInt32(1, 0);
  return y.getFloat32(0);


Maybe clarify that the start of the view is aligned and the check below ensures
that constant indices are aligned.

[Vyacheslav Egorov (Google), 2015/01/26 14:57:16]

I was talking about element size (access size). I have amended the comment as
discussed.

+//     as X[C|S], where C is constant byte offset and S is size of the data
+//     type. Obviously X[C|S] and X[K|U] alias if and only if either
+//     C = RoundDown(K, S) or K = RoundDown(C, U).
+//
 // Separating allocations from other objects improves precision of the
 // load forwarding pass because of the following two properties:
 //
 //   - if X can be proven to have no aliases itself (i.e. there is no other SSA
 //     variable that points to X) then no place inside X can be aliased with any
 //     wildcard dependent place (*.f, *.@offs, *[*], *[C]);
 //   - given allocations X and Y no place inside X can be aliased with any place
 //     inside Y even if any of them or both escape.
 //
 // It important to realize that single place can belong to multiple aliases.
@@ skipping 15 matching lines @@
     // being accessed and offset to the field.
     kVMField,
 
     // Indexed location with a non-constant index.
     kIndexed,
 
     // Indexed location with a constant index.
     kConstantIndexed,
   };
 
+  // Size of the element accessed by constant index. Size is only important
+  // for TypedData because those accesses can alias even when constant indexes
+  // are not the same: X[0|4] aliases X[0|2] and X[2|2].
+  enum ElementSize {
+    // If indexed access is not a TypedData access then element size is not
+    // important because there is only a single possible access size depending
+    // on the receiver - X[C] aliases X[K] if and only if C == K.
+    // This is the size set for Array, ImmutableArray, OneByteString and
+    // TwoByteString accesses.
+    kNoSize,
+
+    // 1 byte (Int8List, Uint8List, Uint8ClampedList).
+    kInt8,
+
+    // 2 bytes (Int16List, Uint16List).
+    kInt16,
+
+    // 4 bytes (Int32List, Uint32List, Float32List).
+    kInt32,
+
+    // 8 bytes (Int64List, Uint64List, Float64List).
+    kInt64,
+
+    // 16 bytes (Int32x4List, Float32x4List, Float64x2List).
+    kInt128,
+
+    kLargestElementSize = kInt128,
+  };
+
   Place(const Place& other)
       : ValueObject(),
-        kind_(other.kind_),
-        representation_(other.representation_),
+        flags_(other.flags_),
         instance_(other.instance_),
         raw_selector_(other.raw_selector_),
         id_(other.id_) {
   }
 
   // Construct a place from instruction if instruction accesses any place.
   // Otherwise constructs kNone place.
   Place(Instruction* instr, bool* is_load, bool* is_store)
-      : kind_(kNone),
-        representation_(kNoRepresentation),
+      : flags_(0),
         instance_(NULL),
         raw_selector_(0),
         id_(0) {
     switch (instr->tag()) {
       case Instruction::kLoadField: {
         LoadFieldInstr* load_field = instr->AsLoadField();
-        representation_ = load_field->representation();
+        set_representation(load_field->representation());
         instance_ = load_field->instance()->definition()->OriginalDefinition();
         if (load_field->field() != NULL) {
-          kind_ = kField;
+          set_kind(kField);
           field_ = load_field->field();
         } else {
-          kind_ = kVMField;
+          set_kind(kVMField);
           offset_in_bytes_ = load_field->offset_in_bytes();
         }
         *is_load = true;
         break;
       }
 
       case Instruction::kStoreInstanceField: {
         StoreInstanceFieldInstr* store =
             instr->AsStoreInstanceField();
-        representation_ = store->RequiredInputRepresentation(
-            StoreInstanceFieldInstr::kValuePos);
+        set_representation(store->RequiredInputRepresentation(
+            StoreInstanceFieldInstr::kValuePos));
         instance_ = store->instance()->definition()->OriginalDefinition();
         if (!store->field().IsNull()) {
-          kind_ = kField;
+          set_kind(kField);
           field_ = &store->field();
         } else {
-          kind_ = kVMField;
+          set_kind(kVMField);
           offset_in_bytes_ = store->offset_in_bytes();
         }
         *is_store = true;
         break;
       }
 
       case Instruction::kLoadStaticField:
-        kind_ = kField;
-        representation_ = instr->AsLoadStaticField()->representation();
+        set_kind(kField);
+        set_representation(instr->AsLoadStaticField()->representation());
         field_ = &instr->AsLoadStaticField()->StaticField();
         *is_load = true;
         break;
 
       case Instruction::kStoreStaticField:
-        kind_ = kField;
-        representation_ = instr->AsStoreStaticField()->
-            RequiredInputRepresentation(StoreStaticFieldInstr::kValuePos);
+        set_kind(kField);
+        set_representation(instr->AsStoreStaticField()->
+            RequiredInputRepresentation(StoreStaticFieldInstr::kValuePos));
         field_ = &instr->AsStoreStaticField()->field();
         *is_store = true;
         break;
 
       case Instruction::kLoadIndexed: {
         LoadIndexedInstr* load_indexed = instr->AsLoadIndexed();
-        representation_ = load_indexed->representation();
+        set_representation(load_indexed->representation());
         instance_ = load_indexed->array()->definition()->OriginalDefinition();
-        SetIndex(load_indexed->index()->definition());
+        SetIndex(load_indexed->index()->definition(),
+                 load_indexed->index_scale(),
+                 load_indexed->class_id());
         *is_load = true;
         break;
       }
 
       case Instruction::kStoreIndexed: {
         StoreIndexedInstr* store_indexed = instr->AsStoreIndexed();
-        representation_ = store_indexed->
-            RequiredInputRepresentation(StoreIndexedInstr::kValuePos);
+        set_representation(store_indexed->
+            RequiredInputRepresentation(StoreIndexedInstr::kValuePos));
         instance_ = store_indexed->array()->definition()->OriginalDefinition();
-        SetIndex(store_indexed->index()->definition());
+        SetIndex(store_indexed->index()->definition(),
+                 store_indexed->index_scale(),
+                 store_indexed->class_id());
         *is_store = true;
         break;
       }
 
       default:
         break;
     }
   }
 
   // Create object representing *[*] alias.
   static Place* CreateAnyInstanceAnyIndexAlias(Isolate* isolate,
                                                intptr_t id) {
-    return Wrap(isolate, Place(kIndexed, NULL, 0), id);
+    return Wrap(isolate, Place(
+        EncodeFlags(kIndexed, kNoRepresentation, kNoSize),
+        NULL,
+        0), id);
   }
 
   // Return least generic alias for this place. Given that aliases are
   // essentially sets of places we define least generic alias as a smallest
   // alias that contains this place.
   //
   // We obtain such alias by a simple transformation:
   //
   //    - for places that depend on an instance X.f, X.@offs, X[i], X[C]
   //      we drop X if X is not an allocation because in this case X does not
   //      posess an identity obtaining aliases *.f, *.@offs, *[i] and *[C]
   //      respectively;
   //    - for non-constant indexed places X[i] we drop information about the
   //      index obtaining alias X[*].
+  //    - we drop information about representation, but keep element size
+  //      if any.
   //
   Place ToAlias() const {
     return Place(
-        kind_,
+        RepresentationBits::update(kNoRepresentation, flags_),
         (DependsOnInstance() && IsAllocation(instance())) ? instance() : NULL,
         (kind() == kIndexed) ? 0 : raw_selector_);
   }
 
   bool DependsOnInstance() const {
     switch (kind()) {
       case kField:
       case kVMField:
       case kIndexed:
       case kConstantIndexed:
         return true;
 
       case kNone:
         return false;
     }
 
     UNREACHABLE();
     return false;
   }
 
   // Given instance dependent alias X.f, X.@offs, X[C], X[*] return
   // wild-card dependent alias *.f, *.@offs, *[C] or *[*] respectively.
   Place CopyWithoutInstance() const {
     ASSERT(DependsOnInstance());
-    return Place(kind_, NULL, raw_selector_);
+    return Place(flags_, NULL, raw_selector_);
   }
 
   // Given alias X[C] or *[C] return X[*] and *[*] respectively.
   Place CopyWithoutIndex() const {
-    ASSERT(kind_ == kConstantIndexed);
-    return Place(kIndexed, instance_, 0);
+    ASSERT(kind() == kConstantIndexed);
+    return Place(EncodeFlags(kIndexed, kNoRepresentation, kNoSize),
+                 instance_,
+                 0);
   }
 
+  // Given alias X[ByteOffs|S] and a larger element size S', return
+  // alias X[RoundDown(ByteOffs, S')|S'] - this is the byte offset of a larger
+  // typed array element that contains this typed array element.
+  // In other words this method computes the only possible place with the given
+  // size that can alias this place (due to alignment restrictions).
+  // For example for X[9|kInt8] and target size kInt32 we would return
+  // X[8|kInt32].
+  Place ToLargerElement(ElementSize to) const {
+    ASSERT(kind() == kConstantIndexed);
+    ASSERT(element_size() != kNoSize);
+    ASSERT(element_size() < to);
+    return Place(ElementSizeBits::update(to, flags_),
+                 instance_,
+                 RoundByteOffset(to, index_constant_));
+  }
+
+
   intptr_t id() const { return id_; }
 
-  Kind kind() const { return kind_; }
+  Kind kind() const { return KindBits::decode(flags_); }
 
-  Representation representation() const { return representation_; }
+  Representation representation() const {
+    return RepresentationBits::decode(flags_);
+  }
 
   Definition* instance() const {
     ASSERT(DependsOnInstance());
     return instance_;
   }
 
   void set_instance(Definition* def) {
     ASSERT(DependsOnInstance());
     instance_ = def->OriginalDefinition();
   }
 
   const Field& field() const {
-    ASSERT(kind_ == kField);
+    ASSERT(kind() == kField);
     return *field_;
   }
 
   intptr_t offset_in_bytes() const {
-    ASSERT(kind_ == kVMField);
+    ASSERT(kind() == kVMField);
     return offset_in_bytes_;
   }
 
   Definition* index() const {
-    ASSERT(kind_ == kIndexed);
+    ASSERT(kind() == kIndexed);
     return index_;
   }
 
+  ElementSize element_size() const {
+    return ElementSizeBits::decode(flags_);
+  }
+
   intptr_t index_constant() const {
-    ASSERT(kind_ == kConstantIndexed);
+    ASSERT(kind() == kConstantIndexed);
     return index_constant_;
   }
 
   static const char* DefinitionName(Definition* def) {
     if (def == NULL) {
       return "*";
     } else {
       return Isolate::Current()->current_zone()->PrintToString(
             "v%" Pd, def->ssa_temp_index());
     }
   }
 
   const char* ToCString() const {
-    switch (kind_) {
+    switch (kind()) {
       case kNone:
         return "<none>";
 
       case kField: {
         const char* field_name = String::Handle(field().name()).ToCString();
         if (field().is_static()) {
           return Isolate::Current()->current_zone()->PrintToString(
               "<%s>", field_name);
         } else {
           return Isolate::Current()->current_zone()->PrintToString(
               "<%s.%s>", DefinitionName(instance()), field_name);
         }
       }
 
       case kVMField:
         return Isolate::Current()->current_zone()->PrintToString(
             "<%s.@%" Pd ">",
             DefinitionName(instance()),
             offset_in_bytes());
 
       case kIndexed:
         return Isolate::Current()->current_zone()->PrintToString(
             "<%s[%s]>",
             DefinitionName(instance()),
             DefinitionName(index()));
 
       case kConstantIndexed:
-        return Isolate::Current()->current_zone()->PrintToString(
-            "<%s[%" Pd "]>",
-            DefinitionName(instance()),
-            index_constant());
+        if (element_size() == kNoSize) {
+          return Isolate::Current()->current_zone()->PrintToString(
+              "<%s[%" Pd "]>",
+              DefinitionName(instance()),
+              index_constant());
+        } else {
+          return Isolate::Current()->current_zone()->PrintToString(
+              "<%s[%" Pd "|%" Pd "]>",
+              DefinitionName(instance()),
+              index_constant(),
+              ElementSizeMultiplier(element_size()));
+        }
     }
     UNREACHABLE();
     return "<?>";
   }
 
   bool IsFinalField() const {
     return (kind() == kField) && field().is_final();
   }
 
   intptr_t Hashcode() const {
-    return (kind_ * 63 + reinterpret_cast<intptr_t>(instance_)) * 31 +
-        representation_ * 15 + FieldHashcode();
+    return (flags_ * 63 + reinterpret_cast<intptr_t>(instance_)) * 31 +
+        FieldHashcode();
   }
 
   bool Equals(const Place* other) const {
-    return (kind_ == other->kind_) &&
-        (representation_ == other->representation_) &&
+    return (flags_ == other->flags_) &&
         (instance_ == other->instance_) &&
         SameField(other);
   }
 
   // Create a zone allocated copy of this place and assign given id to it.
   static Place* Wrap(Isolate* isolate, const Place& place, intptr_t id);
 
   static bool IsAllocation(Definition* defn) {
     return (defn != NULL) &&
         (defn->IsAllocateObject() ||
          defn->IsCreateArray() ||
          defn->IsAllocateUninitializedContext() ||
          (defn->IsStaticCall() &&
           defn->AsStaticCall()->IsRecognizedFactory()));
   }
 
  private:
-  Place(Kind kind, Definition* instance, intptr_t selector)
-      : kind_(kind),
-        representation_(kNoRepresentation),
+  Place(uword flags, Definition* instance, intptr_t selector)
+      : flags_(flags),
         instance_(instance),
         raw_selector_(selector),
         id_(0) {
   }
 
   bool SameField(const Place* other) const {
-    return (kind_ == kField) ? (field().raw() == other->field().raw())
-                             : (offset_in_bytes_ == other->offset_in_bytes_);
+    return (kind() == kField) ? (field().raw() == other->field().raw())
+                              : (offset_in_bytes_ == other->offset_in_bytes_);
   }
 
   intptr_t FieldHashcode() const {
-    return (kind_ == kField) ? reinterpret_cast<intptr_t>(field().raw())
-                             : offset_in_bytes_;
+    return (kind() == kField) ? reinterpret_cast<intptr_t>(field().raw())
+                              : offset_in_bytes_;
   }
 
-  void SetIndex(Definition* index) {
+  void set_representation(Representation rep) {
+    flags_ = RepresentationBits::update(rep, flags_);
+  }
+
+  void set_kind(Kind kind) {
+    flags_ = KindBits::update(kind, flags_);
+  }
+
+  void set_element_size(ElementSize scale) {
+    flags_ = ElementSizeBits::update(scale, flags_);
+  }
+
+  void SetIndex(Definition* index, intptr_t scale, intptr_t class_id) {
     ConstantInstr* index_constant = index->AsConstant();
     if ((index_constant != NULL) && index_constant->value().IsSmi()) {
-      kind_ = kConstantIndexed;
-      index_constant_ = Smi::Cast(index_constant->value()).Value();
-    } else {
-      kind_ = kIndexed;
-      index_ = index;
+      const intptr_t index_value = Smi::Cast(index_constant->value()).Value();
+      const ElementSize size = ElementSizeFor(class_id);
+      const bool is_typed_data = (size != kNoSize);
+
+      // If we are writing into the typed data scale the index to
+      // get byte offset. Otherwise ignore the scale.
+      if (!is_typed_data) {
+        scale = 1;
+      }
+
+      // Guard against potential multiplication overflow and negative indices.
+      if ((0 <= index_value) && (index_value < (kMaxInt32 / scale))) {
+        const intptr_t scaled_index = index_value * scale;
+
+        // Guard against unaligned byte offsets.
+        if (!is_typed_data ||
+            Utils::IsAligned(scaled_index, ElementSizeMultiplier(size))) {
+          set_kind(kConstantIndexed);
+          set_element_size(size);
+          index_constant_ = scaled_index;
+          return;
+        }
+      }
+
+      // Fallthrough: create generic _[*] place.
+    }
+
+    set_kind(kIndexed);
+    index_ = index;
+  }
+
+  static uword EncodeFlags(Kind kind, Representation rep, ElementSize scale) {
+    ASSERT((kind == kConstantIndexed) || (scale == kNoSize));
+    return KindBits::encode(kind) |
+        RepresentationBits::encode(rep) |
+        ElementSizeBits::encode(scale);
+  }
+
+  static ElementSize ElementSizeFor(intptr_t class_id) {
+    switch (class_id) {
+      case kArrayCid:
+      case kImmutableArrayCid:
+      case kOneByteStringCid:
+      case kTwoByteStringCid:
+        // Object arrays and strings do not allow accessing them through
+        // different types. No need to attach scale.
+        return kNoSize;
+
+      case kTypedDataInt8ArrayCid:
+      case kTypedDataUint8ArrayCid:
+      case kTypedDataUint8ClampedArrayCid:
+      case kExternalTypedDataUint8ArrayCid:
+      case kExternalTypedDataUint8ClampedArrayCid:
+        return kInt8;
+
+      case kTypedDataInt16ArrayCid:
+      case kTypedDataUint16ArrayCid:
+        return kInt16;
+
+      case kTypedDataInt32ArrayCid:
+      case kTypedDataUint32ArrayCid:
+      case kTypedDataFloat32ArrayCid:
+        return kInt32;
+
+      case kTypedDataInt64ArrayCid:
+      case kTypedDataUint64ArrayCid:
+      case kTypedDataFloat64ArrayCid:
+        return kInt64;
+
+      case kTypedDataInt32x4ArrayCid:
+      case kTypedDataFloat32x4ArrayCid:
+      case kTypedDataFloat64x2ArrayCid:
+        return kInt128;
+
+      default:
+        UNREACHABLE();
+        return kNoSize;
     }
   }
 
-  Kind kind_;
-  Representation representation_;
+  static intptr_t ElementSizeMultiplier(ElementSize size) {
+    return 1 << (static_cast<intptr_t>(size) - static_cast<intptr_t>(kInt8));
+  }
+
+  static intptr_t RoundByteOffset(ElementSize size, intptr_t offset) {
+    return offset & ~(ElementSizeMultiplier(size) - 1);
+  }
+
+  typedef BitField<Kind, 0, 3> KindBits;
+  typedef BitField<Representation, KindBits::kNextBit, 11> RepresentationBits;
+  typedef BitField<
+      ElementSize, RepresentationBits::kNextBit, 3> ElementSizeBits;
+
+  uword flags_;
   Definition* instance_;
   union {
     intptr_t raw_selector_;
     const Field* field_;
     intptr_t offset_in_bytes_;
     intptr_t index_constant_;
     Definition* index_;
   };
 
   intptr_t id_;
@@ skipping 71 matching lines @@
   AliasedSet(Isolate* isolate,
              DirectChainedHashMap<PointerKeyValueTrait<Place> >* places_map,
              ZoneGrowableArray<Place*>* places,
              PhiPlaceMoves* phi_moves)
       : isolate_(isolate),
         places_map_(places_map),
         places_(*places),
         phi_moves_(phi_moves),
         aliases_(5),
         aliases_map_(),
+        typed_data_access_sizes_(),
         representatives_(),
         killed_(),
         aliased_by_effects_(new(isolate) BitVector(isolate, places->length())) {
     InsertAlias(Place::CreateAnyInstanceAnyIndexAlias(isolate_,
         kAnyInstanceAnyIndexAlias));
     for (intptr_t i = 0; i < places_.length(); i++) {
       AddRepresentative(places_[i]);
     }
     ComputeKillSets();
   }
@@ skipping 88 matching lines @@
       if (alias->kind() == Place::kConstantIndexed) {
         if (CanBeAliased(alias->instance())) {
           EnsureSet(&representatives_, kAnyConstantIndexedAlias)->
               Add(place->id());
         }
 
         if (alias->instance() == NULL) {
           EnsureSet(&representatives_, kUnknownInstanceConstantIndexedAlias)->
               Add(place->id());
         }
+
+        // Collect all element sizes used to access TypedData arrays in
+        // the function. This is used to skip sizes without representatives
+        // when computing kill sets.
+        if (alias->element_size() != Place::kNoSize) {
+          typed_data_access_sizes_.Add(alias->element_size());
+        }
       } else if ((alias->kind() == Place::kIndexed) &&
                  CanBeAliased(place->instance())) {
         EnsureSet(&representatives_, kAnyAllocationIndexedAlias)->
             Add(place->id());
       }
 
       if (!IsIndependentFromEffects(place)) {
         aliased_by_effects_->Add(place->id());
       }
     }
@@ skipping 28 matching lines @@
   }
 
   const Place* CanonicalizeAlias(const Place& alias) {
     const Place* canonical = aliases_map_.Lookup(&alias);
     if (canonical == NULL) {
       canonical = Place::Wrap(isolate_,
                               alias,
                               kAnyInstanceAnyIndexAlias + aliases_.length());
       InsertAlias(canonical);
     }
+    ASSERT(aliases_map_.Lookup(&alias) == canonical);
     return canonical;
   }
 
   BitVector* GetRepresentativesSet(intptr_t alias) {
     return (alias < representatives_.length()) ? representatives_[alias] : NULL;
   }
 
   BitVector* EnsureSet(GrowableArray<BitVector*>* sets,
                        intptr_t alias) {
     while (sets->length() <= alias) {
@@ skipping 49 matching lines @@
           AddAllRepresentatives(alias, kAnyAllocationIndexedAlias);
         } else if (CanBeAliased(alias->instance())) {
           // X[*] aliases with X[C].
           // If X can be aliased then X[*] also aliases with *[C], *[*].
           CrossAlias(alias, kAnyInstanceAnyIndexAlias);
           AddAllRepresentatives(alias, kUnknownInstanceConstantIndexedAlias);
         }
         break;
 
       case Place::kConstantIndexed:  // Either X[C] or *[C] alias.
+        if (alias->element_size() != Place::kNoSize) {
+          const bool has_aliased_instance =
+              (alias->instance() != NULL) && CanBeAliased(alias->instance());
+
+          // If this is a TypedData access then X[C|S] aliases larger elements
+          // covering this one X[RoundDown(C, S')|S'] for all S' > S and
+          // all smaller elements being covered by this one X[C'|S'] for
+          // some S' < S and all C' such that C = RoundDown(C', S).
+          // In the loop below it's enough to only propagate aliasing to
+          // larger aliases because propagation is symmetric: smaller aliases
+          // (if there are any) would update kill set for this alias when they
+          // are visited.
+          for (intptr_t i = static_cast<intptr_t>(alias->element_size()) + 1;
+               i <= Place::kLargestElementSize;
+               i++) {
+            // Skip element sizes that a guaranteed to have no representatives.
+            if (!typed_data_access_sizes_.Contains(alias->element_size())) {
+              continue;
+            }
+
+            // X[C|S] aliases with X[RoundDown(C, S')|S'] and likewise
+            // *[C|S] aliases with *[RoundDown(C, S')|S'].
+            const Place larger_alias =
+                alias->ToLargerElement(static_cast<Place::ElementSize>(i));
+            CrossAlias(alias, larger_alias);
+            if (has_aliased_instance) {
+              // If X is an aliased instance then X[C|S] aliases
+              // with *[RoundDown(C, S')|S'].
+              CrossAlias(alias, larger_alias.CopyWithoutInstance());
+            }
+          }
+        }
+
         if (alias->instance() == NULL) {
           // *[C] aliases with X[C], X[*], *[*].
           AddAllRepresentatives(alias, kAnyAllocationIndexedAlias);
           CrossAlias(alias, kAnyInstanceAnyIndexAlias);
         } else {
           // X[C] aliases with X[*].
           // If X can be aliased then X[C] also aliases with *[C], *[*].
           CrossAlias(alias, alias->CopyWithoutIndex());
           if (CanBeAliased(alias->instance())) {
             CrossAlias(alias, alias->CopyWithoutInstance());
@@ skipping 172 matching lines @@
 
   const ZoneGrowableArray<Place*>& places_;
 
   const PhiPlaceMoves* phi_moves_;
 
   // A list of all seen aliases and a map that allows looking up canonical
   // alias object.
   GrowableArray<const Place*> aliases_;
   DirectChainedHashMap<PointerKeyValueTrait<const Place> > aliases_map_;
 
+  SmallSet<Place::ElementSize> typed_data_access_sizes_;
+
   // Maps alias id to set of ids of places representing the alias.
   // Place represents an alias if this alias is least generic alias for
   // the place.
   // (see ToAlias for the definition of least generic alias).
   GrowableArray<BitVector*> representatives_;
 
   // Maps alias id to set of ids of places aliased.
   GrowableArray<BitVector*> killed_;
 
   // Set of ids of places that can be affected by side-effects other than
@@ skipping 2451 matching lines @@
 
   // Insert materializations at environment uses.
   for (intptr_t i = 0; i < exits_collector_.exits().length(); i++) {
     CreateMaterializationAt(
         exits_collector_.exits()[i], alloc, *slots);
   }
 }
 
 
 }  // namespace dart