libgomp: Fix up creation of artificial teams

When not in explicit parallel/target/teams construct, we in some cases create
an artificial parallel with a single thread (either to handle target nowait
or for task reduction purposes).  In those cases, it handled again artificially
created implicit task (created by gomp_new_icv for cases where we needed to write
to some ICVs), but as the testcases show, didn't take into account possibility
of this being done from explicit task(s).  The code would destroy/free the previous
task and replace it with the new implicit task.  If task is an explicit task
(when teams is NULL, all explicit tasks behave like if (0)), it is a pointer to
a local stack variable, so freeing it doesn't work, and additionally we shouldn't
lose the explicit tasks - the new implicit task should instead replace the
ancestor task which is the first implicit one.

2022-10-12  Jakub Jelinek  <jakub@redhat.com>

	* task.c (gomp_create_artificial_team): Fix up handling of invocations
	from within explicit task.
	* target.c (GOMP_target_ext): Likewise.
	* testsuite/libgomp.c/task-7.c: New test.
	* testsuite/libgomp.c/task-8.c: New test.
	* testsuite/libgomp.c-c++-common/task-reduction-17.c: New test.
	* testsuite/libgomp.c-c++-common/task-reduction-18.c: New test.

(cherry picked from commit a58a965eb73253759f6a3e1c7380392557da89c8)

diff --git a/libgomp/target.c b/libgomp/target.c
index 9017458885e9e9fbed0d16b0e41409fd361697a4..fa364b9d79b62bafc2a86ea044f804ea1e321d81 100644 (file)
--- a/libgomp/target.c
+++ b/libgomp/target.c
@@ -2639,6 +2639,7 @@ GOMP_target_ext (int device, void (*fn) (void *), size_t mapnum,
        {
          struct gomp_team *team = gomp_new_team (1);
          struct gomp_task *task = thr->task;
+         struct gomp_task **implicit_task = &task;
          struct gomp_task_icv *icv = task ? &task->icv : &gomp_global_icv;
          team->prev_ts = thr->ts;
          thr->ts.team = team;
@@ -2651,15 +2652,23 @@ GOMP_target_ext (int device, void (*fn) (void *), size_t mapnum,
          thr->ts.static_trip = 0;
          thr->task = &team->implicit_task[0];
          gomp_init_task (thr->task, NULL, icv);
-         if (task)
+         while (*implicit_task
+                && (*implicit_task)->kind != GOMP_TASK_IMPLICIT)
+           implicit_task = &(*implicit_task)->parent;
+         if (*implicit_task)
            {
-             thr->task = task;
+             thr->task = *implicit_task;
              gomp_end_task ();
-             free (task);
+             free (*implicit_task);
              thr->task = &team->implicit_task[0];
            }
          else
            pthread_setspecific (gomp_thread_destructor, thr);
+         if (implicit_task != &task)
+           {
+             *implicit_task = thr->task;
+             thr->task = task;
+           }
        }
       if (thr->ts.team
          && !thr->task->final_task)

diff --git a/libgomp/task.c b/libgomp/task.c
index 828348c4cf4815a3d71e531ae1100392126bd43a..cc0d38e7e57edf1f27d0c3eddf73e59d313639ca 100644 (file)
--- a/libgomp/task.c
+++ b/libgomp/task.c
@@ -2224,6 +2224,7 @@ gomp_create_artificial_team (void)
   struct gomp_task_icv *icv;
   struct gomp_team *team = gomp_new_team (1);
   struct gomp_task *task = thr->task;
+  struct gomp_task **implicit_task = &task;
   icv = task ? &task->icv : &gomp_global_icv;
   team->prev_ts = thr->ts;
   thr->ts.team = team;
@@ -2236,17 +2237,25 @@ gomp_create_artificial_team (void)
   thr->ts.static_trip = 0;
   thr->task = &team->implicit_task[0];
   gomp_init_task (thr->task, NULL, icv);
-  if (task)
+  while (*implicit_task
+        && (*implicit_task)->kind != GOMP_TASK_IMPLICIT)
+    implicit_task = &(*implicit_task)->parent;
+  if (*implicit_task)
     {
-      thr->task = task;
+      thr->task = *implicit_task;
       gomp_end_task ();
-      free (task);
+      free (*implicit_task);
       thr->task = &team->implicit_task[0];
     }
 #ifdef LIBGOMP_USE_PTHREADS
   else
     pthread_setspecific (gomp_thread_destructor, thr);
 #endif
+  if (implicit_task != &task)
+    {
+      *implicit_task = thr->task;
+      thr->task = task;
+    }
 }
 
 /* The format of data is:

diff --git a/libgomp/testsuite/libgomp.c-c++-common/task-reduction-17.c b/libgomp/testsuite/libgomp.c-c++-common/task-reduction-17.c
new file mode 100644 (file)
index 0000000..4a8d1e8
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c-c++-common/task-reduction-17.c
@@ -0,0 +1,36 @@
+/* { dg-do run } */
+
+#include <omp.h>
+#include <stdlib.h>
+
+int a;
+
+int
+main ()
+{
+  #pragma omp task final (1)
+  {
+    if (!omp_in_final ())
+      abort ();
+    #pragma omp task
+    {
+      if (!omp_in_final ())
+       abort ();
+      #pragma omp taskgroup task_reduction (+: a)
+      {
+       if (!omp_in_final ())
+         abort ();
+       #pragma omp task in_reduction (+: a)
+       {
+         ++a;
+         if (!omp_in_final ())
+           abort ();
+       }
+      }
+      if (!omp_in_final ())
+       abort ();
+      #pragma omp taskwait
+    }
+  }
+  return 0;
+}

diff --git a/libgomp/testsuite/libgomp.c-c++-common/task-reduction-18.c b/libgomp/testsuite/libgomp.c-c++-common/task-reduction-18.c
new file mode 100644 (file)
index 0000000..483f440
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c-c++-common/task-reduction-18.c
@@ -0,0 +1,17 @@
+/* { dg-do run } */
+
+int a;
+
+int
+main ()
+{
+  #pragma omp task
+  {
+    #pragma omp taskgroup task_reduction (+: a)
+    {
+      #pragma omp task in_reduction (+: a)
+      ++a;
+    }
+  }
+  return 0;
+}

diff --git a/libgomp/testsuite/libgomp.c/task-7.c b/libgomp/testsuite/libgomp.c/task-7.c
new file mode 100644 (file)
index 0000000..0307575
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c/task-7.c
@@ -0,0 +1,26 @@
+/* { dg-do run } */
+
+#include <omp.h>
+#include <stdlib.h>
+
+int
+main ()
+{
+  #pragma omp task final (1)
+  {
+    if (!omp_in_final ())
+      abort ();
+    #pragma omp task
+    {
+      if (!omp_in_final ())
+       abort ();
+      #pragma omp target nowait
+      if (omp_in_final ())
+       abort ();
+      if (!omp_in_final ())
+       abort ();
+      #pragma omp taskwait
+    }
+  }
+  return 0;
+}

diff --git a/libgomp/testsuite/libgomp.c/task-8.c b/libgomp/testsuite/libgomp.c/task-8.c
new file mode 100644 (file)
index 0000000..f03aef6
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c/task-8.c
@@ -0,0 +1,14 @@
+/* { dg-do run } */
+
+int
+main ()
+{
+  int i = 0;
+  #pragma omp task
+  {
+    #pragma omp target nowait private (i)
+    i = 1;
+    #pragma omp taskwait
+  }
+  return 0;
+}