From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2153) id 5B13838346A8; Tue, 10 May 2022 08:17:41 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 5B13838346A8 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: Jakub Jelinek To: gcc-cvs@gcc.gnu.org Subject: [gcc r10-10608] openmp: Fix up taskloop reduction ICE if taskloop has no iterations [PR100471] X-Act-Checkin: gcc X-Git-Author: Jakub Jelinek X-Git-Refname: refs/heads/releases/gcc-10 X-Git-Oldrev: 9cd6d49d43ff7a8e47ffe5358b2e8fe072ed0e69 X-Git-Newrev: 49bfa539e240cd769179751f18c472f9a4ea2248 Message-Id: <20220510081741.5B13838346A8@sourceware.org> Date: Tue, 10 May 2022 08:17:41 +0000 (GMT) X-BeenThere: gcc-cvs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-cvs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 10 May 2022 08:17:41 -0000 https://gcc.gnu.org/g:49bfa539e240cd769179751f18c472f9a4ea2248 commit r10-10608-g49bfa539e240cd769179751f18c472f9a4ea2248 Author: Jakub Jelinek Date: Tue May 11 09:07:47 2021 +0200 openmp: Fix up taskloop reduction ICE if taskloop has no iterations [PR100471] When a taskloop doesn't have any iterations, GOMP_taskloop* takes an early return, doesn't create any tasks and more importantly, doesn't create a taskgroup and doesn't register task reductions. But, the code emitted in the callers assumes task reductions have been registered and performs the reduction handling and task reduction unregistration. The pointer to the task reduction private variables is reused, on input it is the alignment and only on output it is the pointer, so in the case taskloop with no iterations the caller attempts to dereference the alignment value as if it was a pointer and crashes. We could in the early returns register the task reductions only to have them looped over and unregistered in the caller, but I think it is better to tell the caller there is nothing to task reduce and bypass all that. 2021-05-11 Jakub Jelinek PR middle-end/100471 * omp-low.c (lower_omp_task_reductions): For OMP_TASKLOOP, if data is 0, bypass the reduction loop including GOMP_taskgroup_reduction_unregister call. * taskloop.c (GOMP_taskloop): If GOMP_TASK_FLAG_REDUCTION and not GOMP_TASK_FLAG_NOGROUP, when doing early return clear the task reduction pointer. * testsuite/libgomp.c/task-reduction-4.c: New test. (cherry picked from commit 98acbb3111fcb5e57d5e63d46c0d92f4e53e3c2a) Diff: --- gcc/omp-low.c | 12 +++++++++++- libgomp/taskloop.c | 22 +++++++++++++++++----- libgomp/testsuite/libgomp.c/task-reduction-4.c | 21 +++++++++++++++++++++ 3 files changed, 49 insertions(+), 6 deletions(-) diff --git a/gcc/omp-low.c b/gcc/omp-low.c index 625566acea1..0e46495f724 100644 --- a/gcc/omp-low.c +++ b/gcc/omp-low.c @@ -8295,7 +8295,7 @@ lower_omp_task_reductions (omp_context *ctx, enum tree_code code, tree clauses, tree num_thr_sz = create_tmp_var (size_type_node); tree lab1 = create_artificial_label (UNKNOWN_LOCATION); tree lab2 = create_artificial_label (UNKNOWN_LOCATION); - tree lab3 = NULL_TREE; + tree lab3 = NULL_TREE, lab7 = NULL_TREE; gimple *g; if (code == OMP_FOR || code == OMP_SECTIONS) { @@ -8360,6 +8360,14 @@ lower_omp_task_reductions (omp_context *ctx, enum tree_code code, tree clauses, NULL_TREE, NULL_TREE); tree data = create_tmp_var (pointer_sized_int_node); gimple_seq_add_stmt (end, gimple_build_assign (data, t)); + if (code == OMP_TASKLOOP) + { + lab7 = create_artificial_label (UNKNOWN_LOCATION); + g = gimple_build_cond (NE_EXPR, data, + build_zero_cst (pointer_sized_int_node), + lab1, lab7); + gimple_seq_add_stmt (end, g); + } gimple_seq_add_stmt (end, gimple_build_label (lab1)); tree ptr; if (TREE_CODE (TYPE_SIZE_UNIT (record_type)) == INTEGER_CST) @@ -8723,6 +8731,8 @@ lower_omp_task_reductions (omp_context *ctx, enum tree_code code, tree clauses, g = gimple_build_call (t, 1, build_fold_addr_expr (avar)); } gimple_seq_add_stmt (end, g); + if (lab7) + gimple_seq_add_stmt (end, gimple_build_label (lab7)); t = build_constructor (atype, NULL); TREE_THIS_VOLATILE (t) = 1; gimple_seq_add_stmt (end, gimple_build_assign (avar, t)); diff --git a/libgomp/taskloop.c b/libgomp/taskloop.c index c3476249ef9..1d8ba3a4315 100644 --- a/libgomp/taskloop.c +++ b/libgomp/taskloop.c @@ -51,20 +51,32 @@ GOMP_taskloop (void (*fn) (void *), void *data, void (*cpyfn) (void *, void *), /* If parallel or taskgroup has been cancelled, don't start new tasks. */ if (team && gomp_team_barrier_cancelled (&team->barrier)) - return; + { + early_return: + if ((flags & (GOMP_TASK_FLAG_NOGROUP | GOMP_TASK_FLAG_REDUCTION)) + == GOMP_TASK_FLAG_REDUCTION) + { + struct gomp_data_head { TYPE t1, t2; uintptr_t *ptr; }; + uintptr_t *ptr = ((struct gomp_data_head *) data)->ptr; + /* Tell callers GOMP_taskgroup_reduction_register has not been + called. */ + ptr[2] = 0; + } + return; + } #ifdef TYPE_is_long TYPE s = step; if (step > 0) { if (start >= end) - return; + goto early_return; s--; } else { if (start <= end) - return; + goto early_return; s++; } UTYPE n = (end - start + s) / step; @@ -73,13 +85,13 @@ GOMP_taskloop (void (*fn) (void *), void *data, void (*cpyfn) (void *, void *), if (flags & GOMP_TASK_FLAG_UP) { if (start >= end) - return; + goto early_return; n = (end - start + step - 1) / step; } else { if (start <= end) - return; + goto early_return; n = (start - end - step - 1) / -step; } #endif diff --git a/libgomp/testsuite/libgomp.c/task-reduction-4.c b/libgomp/testsuite/libgomp.c/task-reduction-4.c new file mode 100644 index 00000000000..7ca1d02fa19 --- /dev/null +++ b/libgomp/testsuite/libgomp.c/task-reduction-4.c @@ -0,0 +1,21 @@ +/* PR middle-end/100471 */ + +extern void abort (void); + +int c; + +int +main () +{ +#pragma omp parallel +#pragma omp single + { + int r = 0, i; + #pragma omp taskloop reduction(+:r) + for (i = 0; i < c; i++) + r++; + if (r != 0) + abort (); + } + return 0; +}