Hi,
the S/390 expanders reject operands not being naturally aligned. This
makes the gcc-have-sync-compare-and-swap.c failing.
The attached patch adds an alignment attribute to the data
type used in the check to make it succeed on S/390 again.
In the future perhaps it would be more appropriate to introduce a 128
bit data type supposed to be used for atomic operations. Given that
we already have __int128_t perhaps we should also provide a
__atomic_int128_t? For S/390 we cannot change the alignment of
__int128_t anymore but we would require a stricter alignment for
__atomic_int128_t right from the beginning in order to enable our
atomic hardware instructions. Does that sound reasonable?
Ok for mainline?
Bye,
-Andreas-
2014-02-07 Andreas Krebbel <andreas.kreb...@de.ibm.com>
* gcc.dg/gcc-have-sync-compare-and-swap.c: Align the 16 byte
variable used for atomic operations.
commit 4b91700e39db14f474b030956b14be94794b589c
Author: Andreas Krebbel <kreb...@linux.vnet.ibm.com>
Date: Fri Feb 7 13:59:47 2014 +0100
Add alignment attribute to 128 bit type for atomic operations.
diff --git a/gcc/testsuite/gcc.dg/gcc-have-sync-compare-and-swap.c
b/gcc/testsuite/gcc.dg/gcc-have-sync-compare-and-swap.c
index faed818..5affeba 100644
--- a/gcc/testsuite/gcc.dg/gcc-have-sync-compare-and-swap.c
+++ b/gcc/testsuite/gcc.dg/gcc-have-sync-compare-and-swap.c
@@ -40,10 +40,12 @@ void f8()
#endif
}
+/* aligned (16): On S/390 16 byte compare and swap operations are only
+ available if the memory operand resides on a 16 byte boundary. */
void f16()
{
#ifdef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_16
- typedef int __attribute__ ((__mode__ (__TI__))) ti_int_type;
+ typedef int __attribute__ ((__mode__ (__TI__), aligned (16))) ti_int_type;
ti_int_type ti_int;
__sync_bool_compare_and_swap (&ti_int, (ti_int_type)0, (ti_int_type)1);
#endif
