openmp: Fix ICE with taskgroup at -O0 -fexceptions [PR107001]

The following testcase ICEs because with -O0 -fexceptions GOMP_taskgroup_end
call isn't directly followed by GOMP_RETURN statement, but there are some
conditionals to handle exceptions and we fail to find the correct GOMP_RETURN.

The fix is to treat taskgroup similarly to target data, both of these constructs
emit a try { body } finally { end_call } around the construct's body during
gimplification and we need to see proper construct nesting during gimplification
and omp lowering (including nesting of regions checks), but during omp expansion
we don't really need their nesting anymore, all we need is emit something at
the start of the region and the end of the region is the end API call we've
already emitted during gimplification.  For target data, we weren't adding
GOMP_RETURN statement during omp lowering, so after that pass it is treated
merely like stand-alone omp directives.  This patch does the same for
taskgroup too.

2022-09-24  Jakub Jelinek  <jakub@redhat.com>

	PR c/107001
	* omp-low.cc (lower_omp_taskgroup): Don't add GOMP_RETURN statement
	at the end.
	* omp-expand.cc (build_omp_regions_1): Clarify GF_OMP_TARGET_KIND_DATA
	is not stand-alone directive.  For GIMPLE_OMP_TASKGROUP, also don't
	update parent.
	(omp_make_gimple_edges) <case GIMPLE_OMP_TASKGROUP>: Reset
	cur_region back after new_omp_region.

	* c-c++-common/gomp/pr107001.c: New test.

(cherry picked from commit ad2aab5c816a6fd56b46210c0a4a4c6243da1de9)

diff --git a/gcc/ChangeLog.omp b/gcc/ChangeLog.omp
index 30c3abfc15bf8997ce05b8c459e7ac798c4f23f6..3b27de7994877b3ce511642a4543393068e3f3fc 100644 (file)
--- a/gcc/ChangeLog.omp
+++ b/gcc/ChangeLog.omp
@@ -1,3 +1,17 @@
+2022-09-24  Tobias Burnus  <tobias@codesourcery.com>
+
+       Backport from mainline:
+       2022-09-24  Jakub Jelinek  <jakub@redhat.com>
+
+       PR c/107001
+       * omp-low.cc (lower_omp_taskgroup): Don't add GOMP_RETURN statement
+       at the end.
+       * omp-expand.cc (build_omp_regions_1): Clarify GF_OMP_TARGET_KIND_DATA
+       is not stand-alone directive.  For GIMPLE_OMP_TASKGROUP, also don't
+       update parent.
+       (omp_make_gimple_edges) <case GIMPLE_OMP_TASKGROUP>: Reset
+       cur_region back after new_omp_region.
+
 2022-09-23  Thomas Schwinge  <thomas@codesourcery.com>
 
        Backport from master branch:

diff --git a/gcc/omp-expand.cc b/gcc/omp-expand.cc
index f2fd0ee9e90c290b53affac3048775156ed9eab6..92996685d418df4997f8d87fe7c732d768d4f85a 100644 (file)
--- a/gcc/omp-expand.cc
+++ b/gcc/omp-expand.cc
@@ -10850,7 +10850,10 @@ build_omp_regions_1 (basic_block bb, struct omp_region *parent,
                case GF_OMP_TARGET_KIND_OACC_ENTER_DATA:
                case GF_OMP_TARGET_KIND_OACC_EXIT_DATA:
                case GF_OMP_TARGET_KIND_OACC_DECLARE:
-                 /* ..., other than for those stand-alone directives...  */
+                 /* ..., other than for those stand-alone directives...
+                    To be precise, target data isn't stand-alone, but
+                    gimplifier put the end API call into try finally block
+                    for it, so omp expansion can treat it as such.  */
                  region = NULL;
                  break;
                default:
@@ -10866,6 +10869,11 @@ build_omp_regions_1 (basic_block bb, struct omp_region *parent,
                   && gimple_omp_task_taskwait_p (stmt))
            /* #pragma omp taskwait depend(...) is a stand-alone directive.  */
            region = NULL;
+         else if (code == GIMPLE_OMP_TASKGROUP)
+           /* #pragma omp taskgroup isn't a stand-alone directive, but
+              gimplifier put the end API call into try finall block
+              for it, so omp expansion can treat it as such.  */
+           region = NULL;
          /* ..., this directive becomes the parent for a new region.  */
          if (region)
            parent = region;
@@ -11065,13 +11073,18 @@ omp_make_gimple_edges (basic_block bb, struct omp_region **region,
     case GIMPLE_OMP_MASTER:
     case GIMPLE_OMP_MASKED:
     case GIMPLE_OMP_SCOPE:
-    case GIMPLE_OMP_TASKGROUP:
     case GIMPLE_OMP_CRITICAL:
     case GIMPLE_OMP_SECTION:
       cur_region = new_omp_region (bb, code, cur_region);
       fallthru = true;
       break;
 
+    case GIMPLE_OMP_TASKGROUP:
+      cur_region = new_omp_region (bb, code, cur_region);
+      fallthru = true;
+      cur_region = cur_region->outer;
+      break;
+
     case GIMPLE_OMP_TASK:
       cur_region = new_omp_region (bb, code, cur_region);
       fallthru = true;

diff --git a/gcc/omp-low.cc b/gcc/omp-low.cc
index da7e262a27cbfd45a3e8025123055b7bf2089b13..85a462aaf94ca2600c55de20c80ee4e727db13d4 100644 (file)
--- a/gcc/omp-low.cc
+++ b/gcc/omp-low.cc
@@ -10417,7 +10417,6 @@ lower_omp_taskgroup (gimple_stmt_iterator *gsi_p, omp_context *ctx)
   gimple_bind_add_seq (bind, gimple_omp_body (stmt));
   gimple_omp_set_body (stmt, NULL);
 
-  gimple_bind_add_stmt (bind, gimple_build_omp_return (true));
   gimple_bind_add_seq (bind, dseq);
 
   pop_gimplify_context (bind);

diff --git a/gcc/testsuite/ChangeLog.omp b/gcc/testsuite/ChangeLog.omp
index 43968b7a28e357af8ecde510b11ac727426a25bb..0d452cbd6908faa48c9503b0d5ba8c775d4a4acc 100644 (file)
--- a/gcc/testsuite/ChangeLog.omp
+++ b/gcc/testsuite/ChangeLog.omp
@@ -1,3 +1,11 @@
+2022-09-24  Tobias Burnus  <tobias@codesourcery.com>
+
+       Backport from mainline:
+       2022-09-24  Jakub Jelinek  <jakub@redhat.com>
+
+       PR c/107001
+       * c-c++-common/gomp/pr107001.c: New test.
+
 2022-09-24  Tobias Burnus  <tobias@codesourcery.com>
 
        Backport from mainline:

diff --git a/gcc/testsuite/c-c++-common/gomp/pr107001.c b/gcc/testsuite/c-c++-common/gomp/pr107001.c
new file mode 100644 (file)
index 0000000..9c19d9b
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/gomp/pr107001.c
@@ -0,0 +1,14 @@
+/* PR c/107001 */
+/* { dg-do compile } */
+/* { dg-options "-O0 -fopenmp -fexceptions" } */
+/* { dg-require-effective-target exceptions } */
+
+void bar (void);
+void foo (void)
+{
+  #pragma omp taskgroup
+  {
+    #pragma omp taskgroup
+    bar ();
+  }
+}