Hi! pthread_setspecific second argument is const void *, so that one can call it even with pointers to const, but the function only stores the pointer and does nothing else, so the new assumption of -Wmaybe-uninitialized that functions taking such pointers will read from what those pointers will point to is wrong. Maybe it would be useful to have some whitelist of functions that surely don't do that.
Anyway, in this case it is easy to workaround the warning by moving the pthread_setspecific call after the initialization without slowing anything down. I don't have access to a target without TLS support, so tested just by manually commenting out #define HAVE_TLS 1 in libgomp config.h , verifying the warning is gone and eyeballing -fdump-tree-{gimple,optimized}. Committed to trunk. 2021-04-09 Jakub Jelinek <ja...@redhat.com> PR libgomp/99984 * team.c (gomp_thread_start): Call pthread_setspecific for !(defined HAVE_TLS || defined USE_EMUTLS) only after local_thr has been initialized to avoid false positive warning. --- libgomp/team.c.jj 2021-02-26 21:58:48.489853641 +0100 +++ libgomp/team.c 2021-04-09 10:03:09.355482978 +0200 @@ -78,7 +78,6 @@ gomp_thread_start (void *xdata) #else struct gomp_thread local_thr; thr = &local_thr; - pthread_setspecific (gomp_tls_key, thr); #endif gomp_sem_init (&thr->release, 0); @@ -92,6 +91,9 @@ gomp_thread_start (void *xdata) #ifdef GOMP_NEEDS_THREAD_HANDLE thr->handle = data->handle; #endif +#if !(defined HAVE_TLS || defined USE_EMUTLS) + pthread_setspecific (gomp_tls_key, thr); +#endif thr->ts.team->ordered_release[thr->ts.team_id] = &thr->release; Jakub