[builtins] Introduce proper Float64Tan operator.

src/compiler/mips64/code-generator-mips64.cc

 // 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.
 
 #include "src/ast/scopes.h"
 #include "src/compiler/code-generator.h"
 #include "src/compiler/code-generator-impl.h"
 #include "src/compiler/gap-resolver.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/osr.h"
@@ skipping 768 matching lines @@
       break;
     case kIeee754Float64Log2:
       ASSEMBLE_IEEE754_UNOP(log2);
       break;
     case kIeee754Float64Log10:
       ASSEMBLE_IEEE754_UNOP(log10);
       break;
     case kIeee754Float64Sin:
       ASSEMBLE_IEEE754_UNOP(sin);
       break;
+    case kIeee754Float64Tan:
+      ASSEMBLE_IEEE754_UNOP(tan);
+      break;
     case kMips64Add:
       __ Addu(i.OutputRegister(), i.InputRegister(0), i.InputOperand(1));
       break;
     case kMips64Dadd:
       __ Daddu(i.OutputRegister(), i.InputRegister(0), i.InputOperand(1));
       break;
     case kMips64DaddOvf:
       // Pseudo-instruction used for overflow/branch. No opcode emitted here.
       break;
     case kMips64Sub:
@@ skipping 1519 matching lines @@
       padding_size -= v8::internal::Assembler::kInstrSize;
     }
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8