https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80547
--- Comment #8 from Tom de Vries <vries at gcc dot gnu.org> --- (In reply to Thomas Schwinge from comment #1) > An additional observation: for host fallback (adding an "if(0)" clause to > both the OpenMP and OpenACC directives, for example), the OpenMP code still > works, but for OpenACC, we then get a result of "x = 23", so apparently the > reduction computation/finalization code is being skipped in this case. > (Let's please make this a separate PR if it's not directly related to this > one here.) Filed PR88852 - "[openacc] Host fallback doesn't create private copy for reduction var on gang clause"