Revert "Hid inline assembly behind a macro". The MEMORY_BARRIER code is OK, and the use of inline assembly code is OK to tame the optimizer is OK; but its confusing because the interactions are not readily apparent.

misc.h

@@ -61,17 +61,6 @@
 # pragma GCC diagnostic ignored "-Wunused-parameter"
 #endif
 
-#if defined(_MSC_VER) && (_MSC_VER >= 1400)
-# pragma intrinsic(_ReadWriteBarrier)
-# define MEMORY_BARRIER() _ReadWriteBarrier()
-#elif defined(_INTEL_COMPILER)
-# define MEMORY_BARRIER() __memory_barrier()
-#elif defined(__GNUC__) || defined(__clang__)
-# define MEMORY_BARRIER() __asm__ __volatile__ ("" ::: "memory")
-#else
-# define MEMORY_BARRIER()
-#endif
-
 NAMESPACE_BEGIN(CryptoPP)
 
 // ************** compile-time assertion ***************

smartptr.h

@@ -3,7 +3,6 @@
 
 #include "config.h"
 #include "stdcpp.h"
-#include "misc.h"
 #include "trap.h"
 
 NAMESPACE_BEGIN(CryptoPP)
@@ -52,8 +51,11 @@ template <class T> simple_ptr<T>::~simple_ptr()
 	delete m_p;
 	m_p = NULL;
 	
-	// https://github.com/weidai11/cryptopp/issues/6
-	MEMORY_BARRIER();
+#ifdef __GNUC__
+	// From Andrew Haley (GCC Dev), to tame the optimizer so the assignment is always performed.
+	// See "Disable optimizations in one function" on the GCC mailing list.
+	asm volatile ("" : : : "memory");
+#endif
 }
 
 template <class T> class member_ptr