Hi,
on S/390 128 bit atomic operations are not allowed for misaligned
operands. The expanders are supposed to FAIL in that case. While it
works for the other routines atomic_load/store it does not work
currently during compare and swap expansion.
The patch just turns an expand_insn into maybe_expand_insn to allow
other alternatives to be chosen when the expander fails.
The patch is required to fix many c11-atomic* testcases on S/390.
gcc.dg/atomic/c11-atomic-exec-5.c still fails since
TARGET_ATOMIC_ASSIGN_EXPAND_FENV is not defined yet.
Ok for mainline?
2014-02-07 Andreas Krebbel <andreas.kreb...@de.ibm.com>
* optabs.c (expand_atomic_compare_and_swap): Allow expander to
fail.
commit 63b1953fadae985ef8302159dacbfc8bf541ec1f
Author: Andreas Krebbel <kreb...@linux.vnet.ibm.com>
Date: Fri Feb 7 12:50:50 2014 +0100
optabs: Allow compare and swap expanders to fail
diff --git a/gcc/optabs.c b/gcc/optabs.c
index e36fd13..cec25a4 100644
--- a/gcc/optabs.c
+++ b/gcc/optabs.c
@@ -7383,12 +7383,13 @@ expand_atomic_compare_and_swap (rtx *ptarget_bool, rtx
*ptarget_oval,
create_integer_operand (&ops[5], is_weak);
create_integer_operand (&ops[6], succ_model);
create_integer_operand (&ops[7], fail_model);
- expand_insn (icode, 8, ops);
-
- /* Return success/failure. */
- target_bool = ops[0].value;
- target_oval = ops[1].value;
- goto success;
+ if (maybe_expand_insn (icode, 8, ops))
+ {
+ /* Return success/failure. */
+ target_bool = ops[0].value;
+ target_oval = ops[1].value;
+ goto success;
+ }
}
/* Otherwise fall back to the original __sync_val_compare_and_swap
