+2010-11-24 Ken Werner <ken.werner@de.ibm.com>
+
+ * sysdeps/unix/sysv/linux/arm/nptl/bits/atomic.h (atomic_full_barrier,
+ __arch_compare_and_exchange_val_32_acq): Use the atomic builtins
+ provided by GCC if __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 is defined.
+
2010-11-22 Andreas Schwab <schwab@redhat.com>
* sysdeps/arm/preconfigure: Only modify CFLAGS when configuring
void __arm_link_error (void);
-#ifdef __thumb2__
+/* Use the atomic builtins provided by GCC in case the backend provides
+ a pattern to do this efficiently. */
+
+#ifdef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
+#define atomic_full_barrier() __sync_synchronize ()
+#elif defined __thumb2__
#define atomic_full_barrier() \
__asm__ __volatile__ \
("movw\tip, #0x0fa0\n\t" \
#define __arch_compare_and_exchange_val_16_acq(mem, newval, oldval) \
({ __arm_link_error (); oldval; })
+#ifdef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
+#define __arch_compare_and_exchange_val_32_acq(mem, newval, oldval) \
+ __sync_val_compare_and_swap ((mem), (oldval), (newval))
+
/* It doesn't matter what register is used for a_oldval2, but we must
specify one to work around GCC PR rtl-optimization/21223. Otherwise
it may cause a_oldval or a_tmp to be moved to a different register. */
-#ifdef __thumb2__
+#elif defined __thumb2__
/* Thumb-2 has ldrex/strex. However it does not have barrier instructions,
so we still need to use the kernel helper. */
#define __arch_compare_and_exchange_val_32_acq(mem, newval, oldval) \