From c51ec0a3d68c86ba9b2e2d0c61556fee8308d570 Mon Sep 17 00:00:00 2001
From: Andrew MacLeod <amacleod@redhat.com>
Date: Wed, 8 Feb 2012 15:26:02 +0000
Subject: [PATCH] optabs.c (expand_atomic_load): Do not assume compare_and_swap
will succeed for larger than word integers.
* optabs.c (expand_atomic_load): Do not assume compare_and_swap will
succeed for larger than word integers.
From-SVN: r184009
---
gcc/ChangeLog | 5 +++++
gcc/optabs.c | 9 ++++++---
2 files changed, 11 insertions(+), 3 deletions(-)
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 71cdd934b69b..1c56ebe37b8e 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 87cce8ef4b04..b0ecdf0513ee 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. */
--
GitLab