Greetings. This is just a ping about a one-liner. The original email was here and is inlined below.
https://gcc.gnu.org/ml/gcc-patches/2014-10/msg02465.html A missing cast causes the compare value to be truncated, resulting in spurious CAS failures. The problem manifested in a new port I'm working on as a failure in test gcc.dg/atomic/c11-atomic-exec-2.c, and I've confirmed that this patch fixes it. I also verified that x86_64-unknown-linux still bootstraps (which is admittedly vacuous, since x86-64 doesn't exercise this code). 2014-10-23 Andrew Waterman <water...@cs.berkeley.edu> * cas_n.c (libat_compare_exchange): Add missing cast. --- libatomic/cas_n.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libatomic/cas_n.c b/libatomic/cas_n.c index 801262d..a885afa 100644 --- a/libatomic/cas_n.c +++ b/libatomic/cas_n.c @@ -70,7 +70,7 @@ SIZE(libat_compare_exchange) (UTYPE *mptr, UTYPE *eptr, UTYPE newval, mask = -1; } - weval = *eptr << shift; + weval = (UWORD)*eptr << shift; wnewval = (UWORD)newval << shift; woldval = __atomic_load_n (wptr, __ATOMIC_RELAXED); do -- 2.1.1
