Revert of Remove SIMD.js from V8.

src/code-stub-assembler.h

 // 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.
 
 #ifndef V8_CODE_STUB_ASSEMBLER_H_
 #define V8_CODE_STUB_ASSEMBLER_H_
 
 #include <functional>
 
 #include "src/compiler/code-assembler.h"
@@ skipping 288 matching lines @@
   }
 
   void BranchIfFloat64IsNaN(Node* value, Label* if_true, Label* if_false) {
     Branch(Float64Equal(value, value), if_false, if_true);
   }
 
   // Branches to {if_true} if ToBoolean applied to {value} yields true,
   // otherwise goes to {if_false}.
   void BranchIfToBooleanIsTrue(Node* value, Label* if_true, Label* if_false);
 
+  void BranchIfSimd128Equal(Node* lhs, Node* lhs_map, Node* rhs, Node* rhs_map,
+                            Label* if_equal, Label* if_notequal);
+  void BranchIfSimd128Equal(Node* lhs, Node* rhs, Label* if_equal,
+                            Label* if_notequal) {
+    BranchIfSimd128Equal(lhs, LoadMap(lhs), rhs, LoadMap(rhs), if_equal,
+                         if_notequal);
+  }
+
   void BranchIfJSReceiver(Node* object, Label* if_true, Label* if_false);
   void BranchIfJSObject(Node* object, Label* if_true, Label* if_false);
 
   enum class FastJSArrayAccessMode { INBOUNDS_READ, ANY_ACCESS };
   void BranchIfFastJSArray(Node* object, Node* context,
                            FastJSArrayAccessMode mode, Label* if_true,
                            Label* if_false);
 
   // Load value from current frame by given offset in bytes.
   Node* LoadFromFrame(int offset, MachineType rep = MachineType::AnyTagged());
@@ skipping 1063 matching lines @@
   }
 #else
 #define CSA_SLOW_ASSERT(csa, x) ((void)0)
 #endif
 
 DEFINE_OPERATORS_FOR_FLAGS(CodeStubAssembler::AllocationFlags);
 
 }  // namespace internal
 }  // namespace v8
 #endif  // V8_CODE_STUB_ASSEMBLER_H_