re PR libgomp/32468 (number of threads in a parallel region depends on number of SECTIONs and MAX_THREADS)

	PR libgomp/32468
	* omp-low.c (check_combined_parallel): New function.
	(lower_omp_parallel): Call it via walk_stmts, set
	OMP_PARALLEL_COMBINED if appropriate.
	(determine_parallel_type): If OMP_FOR resp. OMP_SECTIONS
	isn't the only statement in WS_ENTRY_BB or OMP_RETURN
	the only one in PAR_EXIT_BB and not OMP_PARALLEL_COMBINED,
	don't consider it as combined parallel.

	* gcc.dg/gomp/pr32468-1.c: New test.

From-SVN: r126226

4 files changed, 156 insertions, 2 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index f651d00..164af03 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,14 @@
+2007-07-02  Jakub Jelinek  <jakub@redhat.com>
+
+	PR libgomp/32468
+	* omp-low.c (check_combined_parallel): New function.
+	(lower_omp_parallel): Call it via walk_stmts, set
+	OMP_PARALLEL_COMBINED if appropriate.
+	(determine_parallel_type): If OMP_FOR resp. OMP_SECTIONS
+	isn't the only statement in WS_ENTRY_BB or OMP_RETURN
+	the only one in PAR_EXIT_BB and not OMP_PARALLEL_COMBINED,
+	don't consider it as combined parallel.
+
 2007-07-02  Richard Sandiford  <richard@codesourcery.com>
 
 	* configure.ac (gcc_gxx_include_dir): Use $(libsubdir_to_prefix).
diff --git a/gcc/omp-low.c b/gcc/omp-low.c
index 700645f..fce9975 100644
--- a/gcc/omp-low.c
+++ b/gcc/omp-low.c
@@ -385,9 +385,12 @@ determine_parallel_type (struct omp_region *region)
 
   if (single_succ (par_entry_bb) == ws_entry_bb
       && single_succ (ws_exit_bb) == par_exit_bb
-      && workshare_safe_to_combine_p (par_entry_bb, ws_entry_bb))
+      && workshare_safe_to_combine_p (par_entry_bb, ws_entry_bb)
+      && (OMP_PARALLEL_COMBINED (last_stmt (par_entry_bb))
+	  || (last_and_only_stmt (ws_entry_bb)
+	      && last_and_only_stmt (par_exit_bb))))
     {
-      tree ws_stmt = last_stmt (region->inner->entry);
+      tree ws_stmt = last_stmt (ws_entry_bb);
 
       if (region->inner->type == OMP_FOR)
 	{
@@ -4060,6 +4063,28 @@ lower_omp_for (tree *stmt_p, omp_context *ctx)
   *stmt_p = new_stmt;
 }
 
+/* Callback for walk_stmts.  Check if *TP only contains OMP_FOR
+   or OMP_PARALLEL.  */
+
+static tree
+check_combined_parallel (tree *tp, int *walk_subtrees, void *data)
+{
+  struct walk_stmt_info *wi = data;
+  int *info = wi->info;
+
+  *walk_subtrees = 0;
+  switch (TREE_CODE (*tp))
+    {
+    case OMP_FOR:
+    case OMP_SECTIONS:
+      *info = *info == 0 ? 1 : -1;
+      break;
+    default:
+      *info = -1;
+      break;
+    }
+  return NULL;
+}
 
 /* Lower the OpenMP parallel directive in *STMT_P.  CTX holds context
    information for the directive.  */
@@ -4077,6 +4102,19 @@ lower_omp_parallel (tree *stmt_p, omp_context *ctx)
   par_bind = OMP_PARALLEL_BODY (stmt);
   par_body = BIND_EXPR_BODY (par_bind);
   child_fn = ctx->cb.dst_fn;
+  if (!OMP_PARALLEL_COMBINED (stmt))
+    {
+      struct walk_stmt_info wi;
+      int ws_num = 0;
+
+      memset (&wi, 0, sizeof (wi));
+      wi.callback = check_combined_parallel;
+      wi.info = &ws_num;
+      wi.val_only = true;
+      walk_stmts (&wi, &par_bind);
+      if (ws_num == 1)
+	OMP_PARALLEL_COMBINED (stmt) = 1;
+    }
 
   push_gimplify_context ();
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 7b0e98e..f09c09e 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2007-07-02  Jakub Jelinek  <jakub@redhat.com>
+
+	PR libgomp/32468
+	* gcc.dg/gomp/pr32468-1.c: New test.
+
 2007-07-02  Richard Sandiford  <richard@codesourcery.com>
 
 	* gcc.target/mips/mips.exp (setup_mips_tests): Treat -mfp* as
diff --git a/gcc/testsuite/gcc.dg/gomp/pr32468-1.c b/gcc/testsuite/gcc.dg/gomp/pr32468-1.c
new file mode 100644
index 0000000..4372413
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/gomp/pr32468-1.c
@@ -0,0 +1,100 @@
+/* PR libgomp/32468 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fopenmp -fdump-tree-ompexp" } */
+
+extern int printf (const char *, ...);
+extern int omp_get_thread_num (void), omp_get_num_threads (void);
+extern int bar (void);
+extern int baz (const char *, ...);
+
+void
+f1 (void)
+{
+#pragma omp parallel
+  {
+    baz ("%d/%d\n", omp_get_thread_num (), omp_get_num_threads ());
+    #pragma omp sections
+      {
+	#pragma omp section
+	printf ("section1 %d/%d\n", omp_get_thread_num (), omp_get_num_threads ());
+	#pragma omp section
+	printf ("section2 %d/%d\n", omp_get_thread_num (), omp_get_num_threads ());
+      }
+  }
+}
+
+void
+f2 (void)
+{
+#pragma omp parallel
+  {
+    #pragma omp sections
+      {
+	#pragma omp section
+	printf ("section1 %d/%d\n", omp_get_thread_num (), omp_get_num_threads ());
+	#pragma omp section
+	printf ("section2 %d/%d\n", omp_get_thread_num (), omp_get_num_threads ());
+      }
+    baz ("%d/%d\n", omp_get_thread_num (), omp_get_num_threads ());
+  }
+}
+
+void
+f3 (void)
+{
+#pragma omp parallel
+  {
+    int bb = bar ();
+    #pragma omp sections
+      {
+	#pragma omp section
+	printf ("section1 %d/%d\n", omp_get_thread_num (), omp_get_num_threads ());
+	#pragma omp section
+	printf ("section2 %d/%d\n", omp_get_thread_num (), omp_get_num_threads ());
+      }
+  }
+}
+
+void
+f4 (void)
+{
+  int i;
+#pragma omp parallel
+  {
+    baz ("%d/%d\n", omp_get_thread_num (), omp_get_num_threads ());
+    #pragma omp for schedule (dynamic, 15)
+    for (i = 0; i < 10000; i++)
+      printf ("section1 %d/%d\n", omp_get_thread_num (), omp_get_num_threads ());
+  }
+}
+
+void
+f5 (void)
+{
+  int i;
+#pragma omp parallel
+  {
+    #pragma omp for schedule (dynamic, 15)
+    for (i = 0; i < 10000; i++)
+      printf ("section1 %d/%d\n", omp_get_thread_num (), omp_get_num_threads ());
+    baz ("%d/%d\n", omp_get_thread_num (), omp_get_num_threads ());
+  }
+}
+
+void
+f6 (void)
+{
+  int i;
+#pragma omp parallel
+  {
+    int bb = bar ();
+    #pragma omp for schedule (runtime)
+    for (i = 0; i < 10000; i++)
+      printf ("section1 %d/%d\n", omp_get_thread_num (), omp_get_num_threads ());
+  }
+}
+
+/* There should not be a GOMP_parallel_{loop,sections}* call.  */
+/* { dg-final { scan-tree-dump-times "GOMP_parallel_loop" 0 "ompexp"} } */
+/* { dg-final { scan-tree-dump-times "GOMP_parallel_sections" 0 "ompexp"} } */
+/* { dg-final { cleanup-tree-dump "ompexp" } } */