From 8b60459465252c7d47b58abf83fae2aa84915b03 Mon Sep 17 00:00:00 2001 From: Jakub Jelinek Date: Fri, 18 Dec 2020 21:43:20 +0100 Subject: openmp: Don't optimize shared to firstprivate on task with depend clause The attached testcase is miscompiled, because we optimize shared clauses to firstprivate when task body can't modify the variable even when the task has depend clause. That is wrong, because firstprivate means the variable will be copied immediately when the task is created, while with depend clause some other task might change it later before the dependencies are satisfied and the task should observe the value only after the change. 2020-12-18 Jakub Jelinek * gimplify.c (struct gimplify_omp_ctx): Add has_depend member. (gimplify_scan_omp_clauses): Set it to true if OMP_CLAUSE_DEPEND appears on OMP_TASK. (gimplify_adjust_omp_clauses_1, gimplify_adjust_omp_clauses): Force GOVD_WRITTEN on shared variables if task construct has depend clause. * testsuite/libgomp.c/task-6.c: New test. --- libgomp/testsuite/libgomp.c/task-6.c | 47 ++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) create mode 100644 libgomp/testsuite/libgomp.c/task-6.c (limited to 'libgomp/testsuite/libgomp.c/task-6.c') diff --git a/libgomp/testsuite/libgomp.c/task-6.c b/libgomp/testsuite/libgomp.c/task-6.c new file mode 100644 index 0000000..e5fc758 --- /dev/null +++ b/libgomp/testsuite/libgomp.c/task-6.c @@ -0,0 +1,47 @@ +#include +#include + +int +main () +{ + int x = 0, y = 0; + #pragma omp parallel shared(x, y) + #pragma omp master + { + #pragma omp task depend(out:y) shared(x, y) + { + sleep (1); + x = 1; + y = 1; + } + #pragma omp task depend(inout:y) shared(x, y) + { + if (x != 1 || y != 1) + abort (); + y++; + } + } + if (x != 1 || y != 2) + abort (); + x = 0; + y = 0; + #pragma omp parallel + #pragma omp master + { + #pragma omp task depend(out:y) + { + sleep (1); + x = 1; + y = 1; + } + #pragma omp task depend(inout:y) + { + if (x != 1 || y != 1) + abort (); + y++; + } + } + if (x != 1 || y != 2) + abort (); + return 0; +} -- cgit v1.1