X87: [builtins] Introduce proper Float64Tan operator.

src/crankshaft/x87/lithium-codegen-x87.cc

Index: src/crankshaft/x87/lithium-codegen-x87.cc
diff --git a/src/crankshaft/x87/lithium-codegen-x87.cc b/src/crankshaft/x87/lithium-codegen-x87.cc
index d21b34991c015b198911ea5ca7ae2e22f81d0adf..7bf974c6e90f25f48918fb514e3072195df2fb6d 100644
--- a/src/crankshaft/x87/lithium-codegen-x87.cc
+++ b/src/crankshaft/x87/lithium-codegen-x87.cc
@@ -5301,21 +5301,6 @@ void LCodeGen::DoDoubleBits(LDoubleBits* instr) {
 }
 
 
-void LCodeGen::DoConstructDouble(LConstructDouble* instr) {
-  Register hi_reg = ToRegister(instr->hi());
-  Register lo_reg = ToRegister(instr->lo());
-  X87Register result_reg = ToX87Register(instr->result());
-  // Follow below pattern to write a x87 fp register.
-  X87PrepareToWrite(result_reg);
-  __ sub(esp, Immediate(kDoubleSize));
-  __ mov(Operand(esp, 0), lo_reg);
-  __ mov(Operand(esp, kPointerSize), hi_reg);
-  __ fld_d(Operand(esp, 0));
-  __ add(esp, Immediate(kDoubleSize));
-  X87CommitWrite(result_reg);
-}
-
-
 void LCodeGen::DoAllocate(LAllocate* instr) {
   class DeferredAllocate final : public LDeferredCode {
    public: