maybe return something like (prev & 0xff) ? On 27 June 2017 at 10:51, Savolainen, Petri (Nokia - FI/Espoo) < petri.savolai...@nokia.com> wrote:
> > > > -----Original Message----- > > From: lng-odp [mailto:lng-odp-boun...@lists.linaro.org] On Behalf Of > Brian > > Brooks > > Sent: Monday, June 26, 2017 9:21 PM > > To: lng-odp@lists.linaro.org > > Subject: [lng-odp] [PATCH] build: better atomics detection > > > > Do not optimize away the result of an atomic operation > > during atomics detection in configure stage of build. > > > > This resolves ipfragreass build breakage with clang on > > 32-bit systems. > > > > Signed-off-by: Brian Brooks <brian.bro...@arm.com> > > --- > > platform/linux-generic/m4/configure.m4 | 9 +++++++-- > > 1 file changed, 7 insertions(+), 2 deletions(-) > > > > diff --git a/platform/linux-generic/m4/configure.m4 b/platform/linux- > > generic/m4/configure.m4 > > index e1197f60..af645e05 100644 > > --- a/platform/linux-generic/m4/configure.m4 > > +++ b/platform/linux-generic/m4/configure.m4 > > @@ -34,10 +34,13 @@ use_libatomic=no > > AC_MSG_CHECKING(whether -latomic is needed for 64-bit atomic built-ins) > > AC_LINK_IFELSE( > > [AC_LANG_SOURCE([[ > > - static int loc; > > + #include <stdint.h> > > + static uint64_t loc; > > int main(void) > > { > > - int prev = __atomic_exchange_n(&loc, 7, __ATOMIC_RELAXED); > > + uint64_t prev = __atomic_exchange_n(&loc, 7, __ATOMIC_RELAXED); > > Wouldn't volatile work. I'd avoid inline asm here if it can be avoided. > > volatile uint64_t prev = ...; > > -Petri > > >
