Revert "Clean up runtime functions for Maths."

src/x64/code-stubs-x64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // 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 857 matching lines @@
   // and may not have contained the exponent value in the first place when the
   // input was a smi.  We reset it with exponent value before bailing out.
   __ j(not_equal, &done);
   __ Cvtlsi2sd(double_exponent, exponent);
 
   // Returning or bailing out.
   Counters* counters = masm->isolate()->counters();
   if (exponent_type_ == ON_STACK) {
     // The arguments are still on the stack.
     __ bind(&call_runtime);
-    __ TailCallRuntime(Runtime::kHiddenMathPow, 2, 1);
+    __ TailCallRuntime(Runtime::kMath_pow_cfunction, 2, 1);
 
     // The stub is called from non-optimized code, which expects the result
     // as heap number in rax.
     __ bind(&done);
     __ AllocateHeapNumber(rax, rcx, &call_runtime);
     __ movsd(FieldOperand(rax, HeapNumber::kValueOffset), double_result);
     __ IncrementCounter(counters->math_pow(), 1);
     __ ret(2 * kPointerSize);
   } else {
     __ bind(&call_runtime);
@@ skipping 4332 matching lines @@
                               return_value_operand,
                               NULL);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64