libgomp: Unbreak gcn offload build

My recent libgomp change apparently broke libgomp build for gcn offloading.
The problem is that gcn, unlike nvptx, doesn't override teams.c source file
and the patch I've committed assumed all the non-LIBGOMP_USE_PTHREADS targets
do not use it.  My understanding is that gcn included omp_get_num_teams
and omp_get_team_num definitions in both icv-device.o and teams.o,
with the definitions only in the former working correctly.

This patch brings gcn into sync with how nvptx does it, that teams.c
is overridden, provides a dummy GOMP_teams_reg and omp_get_{num_teams,team_num}
definitions and icv-device.c doesn't provide those.

2021-11-12  Jakub Jelinek  <jakub@redhat.com>

	PR target/103201
	* config/gcn/icv-device.c (omp_get_num_teams, omp_get_team_num): Move
	to ...
	* config/gcn/teams.c: ... here.  New file.

2 files changed, 54 insertions, 14 deletions

diff --git a/libgomp/config/gcn/icv-device.c b/libgomp/config/gcn/icv-device.c
index 34e0f83..2de46a1f 100644
--- a/libgomp/config/gcn/icv-device.c
+++ b/libgomp/config/gcn/icv-device.c
@@ -52,18 +52,6 @@ omp_get_num_devices (void)
 }
 
 int
-omp_get_num_teams (void)
-{
-  return gomp_num_teams_var + 1;
-}
-
-int __attribute__ ((__optimize__ ("O2")))
-omp_get_team_num (void)
-{
-  return __builtin_gcn_dim_pos (0);
-}
-
-int
 omp_is_initial_device (void)
 {
   /* AMD GCN is an accelerator-only target.  */
@@ -84,7 +72,5 @@ ialias (omp_set_default_device)
 ialias (omp_get_default_device)
 ialias (omp_get_initial_device)
 ialias (omp_get_num_devices)
-ialias (omp_get_num_teams)
-ialias (omp_get_team_num)
 ialias (omp_is_initial_device)
 ialias (omp_get_device_num)
diff --git a/libgomp/config/gcn/teams.c b/libgomp/config/gcn/teams.c
new file mode 100644
index 0000000..40d50d8
--- /dev/null
+++ b/libgomp/config/gcn/teams.c
@@ -0,0 +1,54 @@
+/* Copyright (C) 2015-2021 Free Software Foundation, Inc.
+
+   This file is part of the GNU Offloading and Multi Processing Library
+   (libgomp).
+
+   Libgomp is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3, or (at your option)
+   any later version.
+
+   Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY
+   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+   FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+   more details.
+
+   Under Section 7 of GPL version 3, you are granted additional
+   permissions described in the GCC Runtime Library Exception, version
+   3.1, as published by the Free Software Foundation.
+
+   You should have received a copy of the GNU General Public License and
+   a copy of the GCC Runtime Library Exception along with this program;
+   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* This file defines OpenMP API entry points that accelerator targets are
+   expected to replace.  */
+
+#include "libgomp.h"
+
+void
+GOMP_teams_reg (void (*fn) (void *), void *data, unsigned int num_teams,
+		unsigned int thread_limit, unsigned int flags)
+{
+  (void) fn;
+  (void) data;
+  (void) flags;
+  (void) num_teams;
+  (void) thread_limit;
+}
+
+int
+omp_get_num_teams (void)
+{
+  return gomp_num_teams_var + 1;
+}
+
+int __attribute__ ((__optimize__ ("O2")))
+omp_get_team_num (void)
+{
+  return __builtin_gcn_dim_pos (0);
+}
+
+ialias (omp_get_num_teams)
+ialias (omp_get_team_num)