openmp: Fix up handling of kind(host) and kind(nohost) in ACCEL_COMPILERs [PR103384]

As the testcase shows, we weren't handling kind(host) and kind(nohost) properly
in the ACCEL_COMPILERs, the code written in there is valid for the host
compiler only, where if we are maybe offloaded, we defer resolution after IPA,
otherwise return 0 for kind(nohost) and accept it for kind(host).  Note,
omp_maybe_offloaded is false after IPA.  If ACCEL_COMPILER is defined, it is
the other way around, but also we know we are after IPA.

2021-11-24  Jakub Jelinek  <jakub@redhat.com>

	PR middle-end/103384
gcc/
	* omp-general.c (omp_context_selector_matches): For ACCEL_COMPILER,
	return 0 for kind(host) and continue for kind(nohost).
libgomp/
	* testsuite/libgomp.c/declare-variant-2.c: New test.

1 files changed, 45 insertions, 0 deletions

diff --git a/libgomp/testsuite/libgomp.c/declare-variant-2.c b/libgomp/testsuite/libgomp.c/declare-variant-2.c
new file mode 100644
index 00000000000..666ab20ea5f
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c/declare-variant-2.c
@@ -0,0 +1,45 @@
+/* { dg-do run } */
+
+#include <omp.h>
+#include <stdlib.h>
+
+void
+foo_host (void)
+{
+  if (!omp_is_initial_device ())
+    abort ();
+}
+
+#pragma omp declare variant (foo_host) match (device={kind(host)})
+void
+foo (void)
+{
+  if (omp_is_initial_device ())
+    abort ();
+}
+
+void
+bar_nohost (void)
+{
+  if (omp_is_initial_device ())
+    abort ();
+}
+
+#pragma omp declare variant (bar_nohost) match (device={kind(nohost)})
+void
+bar (void)
+{
+  if (!omp_is_initial_device ())
+    abort ();
+}
+
+int
+main ()
+{
+  #pragma omp target
+  {
+    foo ();
+    bar ();
+  }
+  return 0;
+}