Revert of [builtins] Introduce proper Float64Exp operator.

src/crankshaft/ia32/lithium-codegen-ia32.cc

 // Copyright 2012 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_IA32
 
 #include "src/crankshaft/ia32/lithium-codegen-ia32.h"
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 3407 matching lines @@
   Register input = ToRegister(instr->value());
   Register result = ToRegister(instr->result());
 
   __ Lzcnt(result, input);
 }
 
 
 void LCodeGen::DoMathExp(LMathExp* instr) {
   XMMRegister input = ToDoubleRegister(instr->value());
   XMMRegister result = ToDoubleRegister(instr->result());
-  // Pass one double as argument on the stack.
-  __ PrepareCallCFunction(2, eax);
-  __ movsd(Operand(esp, 0 * kDoubleSize), input);
-  __ CallCFunction(ExternalReference::ieee754_exp_function(isolate()), 2);
-  // Return value is in st(0) on ia32.
-  // Store it into the result register.
-  __ sub(esp, Immediate(kDoubleSize));
-  __ fstp_d(Operand(esp, 0));
-  __ movsd(result, Operand(esp, 0));
-  __ add(esp, Immediate(kDoubleSize));
+  XMMRegister temp0 = double_scratch0();
+  Register temp1 = ToRegister(instr->temp1());
+  Register temp2 = ToRegister(instr->temp2());
+
+  MathExpGenerator::EmitMathExp(masm(), input, result, temp0, temp1, temp2);
 }
 
 void LCodeGen::PrepareForTailCall(const ParameterCount& actual,
                                   Register scratch1, Register scratch2,
                                   Register scratch3) {
 #if DEBUG
   if (actual.is_reg()) {
     DCHECK(!AreAliased(actual.reg(), scratch1, scratch2, scratch3));
   } else {
     DCHECK(!AreAliased(scratch1, scratch2, scratch3));
@@ skipping 1854 matching lines @@
   __ bind(deferred->exit());
   __ bind(&done);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_IA32