[stubs] Cleanup CSA::BitFieldDecode() and friends.

src/builtins/builtins-sharedarraybuffer.cc

 // Copyright 2016 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.
 
 #include "src/builtins/builtins.h"
 #include "src/builtins/builtins-utils.h"
 
 #include "src/code-factory.h"
 
 namespace v8 {
@@ skipping 34 matching lines @@
   a->Bind(&not_smi);
   a->Branch(a->WordEqual(a->LoadInstanceType(tagged),
                          a->Int32Constant(JS_TYPED_ARRAY_TYPE)),
             &is_typed_array, &not_typed_array);
   a->Bind(&not_typed_array);
   a->Goto(&invalid);
 
   // Fail if the array's JSArrayBuffer is not shared.
   a->Bind(&is_typed_array);
   Node* array_buffer = a->LoadObjectField(tagged, JSTypedArray::kBufferOffset);
-  Node* is_buffer_shared = a->BitFieldDecode<JSArrayBuffer::IsShared>(
-      a->LoadObjectField(array_buffer, JSArrayBuffer::kBitFieldSlot));
+  Node* is_buffer_shared =
+      a->IsSetWord32<JSArrayBuffer::IsShared>(a->LoadObjectField(
+          array_buffer, JSArrayBuffer::kBitFieldSlot, MachineType::Uint32()));
   a->Branch(is_buffer_shared, &is_shared, &not_shared);
   a->Bind(&not_shared);
   a->Goto(&invalid);
 
   // Fail if the array's element type is float32, float64 or clamped.
   a->Bind(&is_shared);
   Node* elements_instance_type = a->LoadInstanceType(
       a->LoadObjectField(tagged, JSObject::kElementsOffset));
   STATIC_ASSERT(FIXED_INT8_ARRAY_TYPE < FIXED_FLOAT32_ARRAY_TYPE);
   STATIC_ASSERT(FIXED_INT16_ARRAY_TYPE < FIXED_FLOAT32_ARRAY_TYPE);
@@ skipping 190 matching lines @@
                  a->WordShl(index_word, 2), value_word32);
   a->Return(value_integer);
 
   // This shouldn't happen, we've already validated the type.
   a->Bind(&other);
   a->Return(a->Int32Constant(0));
 }
 
 }  // namespace internal
 }  // namespace v8