8961daae4a
This commit fixes an issue seem with some older versions of gcc (verified to occur in gcc 6.x) where on x86_64 systems the acquire memory barrier in C11 atomics acts as a no-op. On these systems the three memory barriers should all be equivalent. This is related to the error fixed in open-mpi/ompi@30119ee. References #6655. Signed-off-by: Nathan Hjelm <hjelmn@google.com>