Fix omp-low ICE for indirect references based off component access [PR103642]

This issue was triggered after the patch extending syntax for component access
in map clauses in commit 0ab29cf0bb68960c1f87405f14b4fb2109254e2f.

In gimplify_scan_omp_clauses, the case for handling indirect accesses (which
creates firstprivate ptr and zero-length array section map for such decls) was
erroneously went into for non-pointer cases (here being the base struct decl),
so added the
appropriate checks there.

Added new testcase is a compile only test for the ICE. The original omptests
t-partial-struct test actually should not execute correctly, because for
map(t.s->a[:N]), map(t.s[:1]) is not implicitly mapped, thus the entire
offloaded access does not work as is (fixing that omptests test is out of
scope here).

2022-01-27  Chung-Lin Tang  <cltang@codesourcery.com>

	PR middle-end/103642

gcc/ChangeLog:

	* gimplify.cc (gimplify_scan_omp_clauses): Do not do indir_p handling
	for non-pointer or non-reference-to-pointer cases.

gcc/testsuite/ChangeLog:

	* c-c++-common/gomp/pr103642.c: New test.

2 files changed, 38 insertions, 1 deletions

diff --git a/gcc/gimplify.cc b/gcc/gimplify.cc
index bf2f60c..cd4b613 100644
--- a/gcc/gimplify.cc
+++ b/gcc/gimplify.cc
@@ -9552,7 +9552,10 @@ gimplify_scan_omp_clauses (tree *list_p, gimple_seq *pre_p,
 			  == REFERENCE_TYPE))
 		    decl = TREE_OPERAND (decl, 0);
 		}
-	      if (decl != orig_decl && DECL_P (decl) && indir_p)
+	      if (decl != orig_decl && DECL_P (decl) && indir_p
+		  && (TREE_CODE (TREE_TYPE (decl)) == POINTER_TYPE
+		      || (decl_ref
+			  && TREE_CODE (TREE_TYPE (decl_ref)) == POINTER_TYPE)))
 		{
 		  gomp_map_kind k
 		    = ((code == OACC_EXIT_DATA || code == OMP_TARGET_EXIT_DATA)
diff --git a/gcc/testsuite/c-c++-common/gomp/pr103642.c b/gcc/testsuite/c-c++-common/gomp/pr103642.c
new file mode 100644
index 0000000..bbd0896
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/gomp/pr103642.c
@@ -0,0 +1,34 @@
+/* PR middle-end/103642 */
+/* { dg-do compile } */
+
+#include <stdlib.h>
+
+typedef struct
+{
+  int *a;
+} S;
+
+typedef struct
+{
+  S *s;
+  int *ptr;
+} T;
+
+#define N 10
+
+int main (void)
+{
+  T t;
+  t.s = (S *) malloc (sizeof (S));
+  t.s->a = (int *) malloc (sizeof(int) * N);
+
+  #pragma omp target map(from: t.s->a[:N])
+  {
+    t.s->a[0] = 1;
+  }
+
+  free (t.s->a);
+  free (t.s);
+
+  return 0;
+}