> -----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
