diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 71cdd934b69b06fbb934d8a1bf0ca779b396daa5..1c56ebe37b8e0232f9859f0f8b9be81956b1586c 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 87cce8ef4b0430a0f1b2dd929d2c1b3af1817a76..b0ecdf0513eef86514f07b3f9df14e2d9de05d96 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. */