[builtins] Introduce proper base::ieee754::log.

src/crankshaft/x64/lithium-codegen-x64.cc

 // Copyright 2013 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.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/crankshaft/x64/lithium-codegen-x64.h"
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 3594 matching lines @@
   XMMRegister result = ToDoubleRegister(instr->result());
   XMMRegister temp0 = double_scratch0();
   Register temp1 = ToRegister(instr->temp1());
   Register temp2 = ToRegister(instr->temp2());
 
   MathExpGenerator::EmitMathExp(masm(), input, result, temp0, temp1, temp2);
 }
 
 
 void LCodeGen::DoMathLog(LMathLog* instr) {
-  DCHECK(instr->value()->Equals(instr->result()));
-  XMMRegister input_reg = ToDoubleRegister(instr->value());
-  XMMRegister xmm_scratch = double_scratch0();
-  Label positive, done, zero;
-  __ Xorpd(xmm_scratch, xmm_scratch);
-  __ Ucomisd(input_reg, xmm_scratch);
-  __ j(above, &positive, Label::kNear);
-  __ j(not_carry, &zero, Label::kNear);
-  __ Pcmpeqd(input_reg, input_reg);
-  __ jmp(&done, Label::kNear);
-  __ bind(&zero);
-  ExternalReference ninf =
-      ExternalReference::address_of_negative_infinity();
-  Operand ninf_operand = masm()->ExternalOperand(ninf);
-  __ Movsd(input_reg, ninf_operand);
-  __ jmp(&done, Label::kNear);
-  __ bind(&positive);
-  __ fldln2();
-  __ subp(rsp, Immediate(kDoubleSize));
-  __ Movsd(Operand(rsp, 0), input_reg);
-  __ fld_d(Operand(rsp, 0));
-  __ fyl2x();
-  __ fstp_d(Operand(rsp, 0));
-  __ Movsd(input_reg, Operand(rsp, 0));
-  __ addp(rsp, Immediate(kDoubleSize));
-  __ bind(&done);
+  DCHECK(ToDoubleRegister(instr->value()).is(xmm0));
+  DCHECK(ToDoubleRegister(instr->result()).is(xmm0));
+  __ PrepareCallCFunction(1);
+  __ CallCFunction(ExternalReference::ieee754_log_function(isolate()), 1);
 }
 
 
 void LCodeGen::DoMathClz32(LMathClz32* instr) {
   Register input = ToRegister(instr->value());
   Register result = ToRegister(instr->result());
 
   __ Lzcntl(result, input);
 }
 
@@ skipping 1972 matching lines @@
   __ bind(deferred->exit());
   __ bind(&done);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64