[builtins] Introduce proper Float64Tan operator.

src/crankshaft/mips/lithium-codegen-mips.cc

 // Copyright 2012 the V8 project authors. All rights reserved.7
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 4996 matching lines @@
   DoubleRegister value_reg = ToDoubleRegister(instr->value());
   Register result_reg = ToRegister(instr->result());
   if (instr->hydrogen()->bits() == HDoubleBits::HIGH) {
     __ FmoveHigh(result_reg, value_reg);
   } else {
     __ FmoveLow(result_reg, value_reg);
   }
 }
 
 
-void LCodeGen::DoConstructDouble(LConstructDouble* instr) {
-  Register hi_reg = ToRegister(instr->hi());
-  Register lo_reg = ToRegister(instr->lo());
-  DoubleRegister result_reg = ToDoubleRegister(instr->result());
-  __ Move(result_reg, lo_reg, hi_reg);
-}
-
-
 void LCodeGen::DoAllocate(LAllocate* instr) {
   class DeferredAllocate final : public LDeferredCode {
    public:
     DeferredAllocate(LCodeGen* codegen, LAllocate* instr)
         : LDeferredCode(codegen), instr_(instr) { }
     void Generate() override { codegen()->DoDeferredAllocate(instr_); }
     LInstruction* instr() override { return instr_; }
 
    private:
     LAllocate* instr_;
@@ skipping 519 matching lines @@
   __ lw(result, FieldMemOperand(scratch,
                                 FixedArray::kHeaderSize - kPointerSize));
   __ bind(deferred->exit());
   __ bind(&done);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8