Avoid doing explicit cast in simulator-a64::get_sp().

src/a64/simulator-a64.h

 // 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 427 matching lines @@
     set_reg(31, value, Reg31IsStackPointer);
   }
 
   int64_t sp() { return xreg(31, Reg31IsStackPointer); }
   int64_t jssp() { return xreg(kJSSPCode, Reg31IsStackPointer); }
   int64_t fp() {
       return xreg(kFramePointerRegCode, Reg31IsStackPointer);
   }
   Instruction* lr() { return reg<Instruction*>(kLinkRegCode); }
 
-  Address get_sp() { return reinterpret_cast<Address>(sp()); }
+  Address get_sp() { return reg<Address>(31, Reg31IsStackPointer); }
 
   // Return 'size' bits of the value of a floating-point register, as the
   // specified type. The value is zero-extended to fill the result.
   //
   // The only supported values of 'size' are kDRegSize and kSRegSize.
   template<typename T>
   T fpreg(unsigned size, unsigned code) const {
     unsigned size_in_bytes = size / 8;
     ASSERT(size_in_bytes <= sizeof(T));
     ASSERT((size == kDRegSize) || (size == kSRegSize));
@@ skipping 397 matching lines @@
   static void UnregisterCTryCatch() {
     Simulator::current(Isolate::Current())->PopAddress();
   }
 };
 
 #endif  // !defined(USE_SIMULATOR)
 
 } }  // namespace v8::internal
 
 #endif  // V8_A64_SIMULATOR_A64_H_