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-rw-r--r--gcc/ChangeLog5
-rw-r--r--gcc/optabs.c9
2 files changed, 11 insertions, 3 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 71cdd93..1c56ebe 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2012-02-08 Andrew MacLeod <amacleod@redhat.com>
+
+ * optabs.c (expand_atomic_load): Do not assume compare_and_swap will
+ always succeed for integers larger than a native word.
+
2012-02-08 Richard Guenther <rguenther@suse.de>
PR rtl-optimization/52170
diff --git a/gcc/optabs.c b/gcc/optabs.c
index 87cce8e..b0ecdf0 100644
--- a/gcc/optabs.c
+++ b/gcc/optabs.c
@@ -7665,9 +7665,12 @@ expand_atomic_load (rtx target, rtx mem, enum memmodel model)
/* Issue val = compare_and_swap (mem, 0, 0).
This may cause the occasional harmless store of 0 when the value is
already 0, but it seems to be OK according to the standards guys. */
- expand_atomic_compare_and_swap (NULL, &target, mem, const0_rtx,
- const0_rtx, false, model, model);
- return target;
+ if (expand_atomic_compare_and_swap (NULL, &target, mem, const0_rtx,
+ const0_rtx, false, model, model))
+ return target;
+ else
+ /* Otherwise there is no atomic load, leave the library call. */
+ return NULL_RTX;
}
/* Otherwise assume loads are atomic, and emit the proper barriers. */