https://gcc.gnu.org/g:48db8148b94ab2d93d9d5301f44950adf2a9c786
commit 48db8148b94ab2d93d9d5301f44950adf2a9c786 Author: Andrew Stubbs <[email protected]> Date: Tue Aug 3 13:45:35 2021 +0100 libgomp amdgcn: Fix issues with dynamic OpenMP thread scaling libgomp/ChangeLog: * config/gcn/bar.h (gomp_barrier_init): Limit thread count to the actual physical number. * config/gcn/team.c (gomp_team_start): Don't attempt to set up threads that do not exist. Diff: --- libgomp/config/gcn/bar.h | 3 +++ libgomp/config/gcn/team.c | 4 ++++ 2 files changed, 7 insertions(+) diff --git a/libgomp/config/gcn/bar.h b/libgomp/config/gcn/bar.h index b62d3af6dee4..4402b10d7e43 100644 --- a/libgomp/config/gcn/bar.h +++ b/libgomp/config/gcn/bar.h @@ -55,6 +55,9 @@ typedef unsigned int gomp_barrier_state_t; static inline void gomp_barrier_init (gomp_barrier_t *bar, unsigned count) { + unsigned actual_thread_count = __builtin_gcn_dim_size (1); + if (count > actual_thread_count) + count = actual_thread_count; bar->total = count; bar->awaited = count; bar->awaited_final = count; diff --git a/libgomp/config/gcn/team.c b/libgomp/config/gcn/team.c index 40827ce8560c..939ee8773256 100644 --- a/libgomp/config/gcn/team.c +++ b/libgomp/config/gcn/team.c @@ -209,6 +209,10 @@ gomp_team_start (void (*fn) (void *), void *data, unsigned nthreads, if (nthreads == 1) return; + unsigned actual_thread_count = __builtin_gcn_dim_size (1); + if (nthreads > actual_thread_count) + nthreads = actual_thread_count; + /* Release existing idle threads. */ for (unsigned i = 1; i < nthreads; ++i) {
