(MEMORY_BARRIER): Define as asm with memory as clobber.

diff --git a/linuxthreads/internals.h b/linuxthreads/internals.h
index 8297c781c82e1d67658e98260c19acc6116a0d3a..2159e70b772e3a601381a1b94480898c4e460240 100644 (file)
--- a/linuxthreads/internals.h
+++ b/linuxthreads/internals.h
@@ -398,11 +398,13 @@ static inline pthread_descr thread_self (void)
 }
 
 /* If MEMORY_BARRIER isn't defined in pt-machine.h, assume the architecture
-   doesn't need a memory barrier instruction (e.g. Intel x86).  Some
-   architectures distinguish between full, read and write barriers.  */
+   doesn't need a memory barrier instruction (e.g. Intel x86).  Still we
+   need the compiler to respect the barrier and emit all outstanding
+   operations which modify memory.  Some architectures distinguish between
+   full, read and write barriers.  */
 
 #ifndef MEMORY_BARRIER
-#define MEMORY_BARRIER()
+#define MEMORY_BARRIER() asm ("" : : : "memory")
 #endif
 #ifndef READ_MEMORY_BARRIER
 #define READ_MEMORY_BARRIER() MEMORY_BARRIER()