[turbofan] Utilize maps from field type tracking to eliminate map checks.

src/compiler/simplified-operator.h

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_COMPILER_SIMPLIFIED_OPERATOR_H_
 #define V8_COMPILER_SIMPLIFIED_OPERATOR_H_
 
 #include <iosfwd>
 
 #include "src/base/compiler-specific.h"
@@ skipping 47 matching lines @@
 V8_EXPORT_PRIVATE BufferAccess const BufferAccessOf(const Operator* op)
     WARN_UNUSED_RESULT;
 
 // An access descriptor for loads/stores of fixed structures like field
 // accesses of heap objects. Accesses from either tagged or untagged base
 // pointers are supported; untagging is done automatically during lowering.
 struct FieldAccess {
   BaseTaggedness base_is_tagged;  // specifies if the base pointer is tagged.
   int offset;                     // offset of the field, without tag.
   MaybeHandle<Name> name;         // debugging only.
+  MaybeHandle<Map> map;           // map of the field value (if known).
   Type* type;                     // type of the field.
   MachineType machine_type;       // machine type of the field.
   WriteBarrierKind write_barrier_kind;  // write barrier hint.
 
   int tag() const { return base_is_tagged == kTaggedBase ? kHeapObjectTag : 0; }
 };
 
 V8_EXPORT_PRIVATE bool operator==(FieldAccess const&, FieldAccess const&);
 bool operator!=(FieldAccess const&, FieldAccess const&);
 
@@ skipping 370 matching lines @@
   Zone* const zone_;
 
   DISALLOW_COPY_AND_ASSIGN(SimplifiedOperatorBuilder);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_SIMPLIFIED_OPERATOR_H_