ARM64: Fix the atomic type width in the 64bit Acquire_Load().

src/atomicops_internals_arm64_gcc.h

 // Copyright 2012 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 291 matching lines @@
     : [value]"r" (value)
     : "memory"
   );  // NOLINT
 }
 
 inline Atomic64 NoBarrier_Load(volatile const Atomic64* ptr) {
   return *ptr;
 }
 
 inline Atomic64 Acquire_Load(volatile const Atomic64* ptr) {
-  Atomic32 value;
+  Atomic64 value;
 
   __asm__ __volatile__ (  // NOLINT
     "ldar %x[value], %[ptr]  \n\t"
     : [value]"=r" (value)
     : [ptr]"Q" (*ptr)
     : "memory"
   );  // NOLINT
 
   return value;
 }
 
 inline Atomic64 Release_Load(volatile const Atomic64* ptr) {
   MemoryBarrier();
   return *ptr;
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_ATOMICOPS_INTERNALS_ARM_GCC_H_