[gcc/devel/omp/gcc-16] C++, OpenMP: Handle ARRAY_TYPE array sections, not just pointers

https://gcc.gnu.org/g:1c5e4c4984afb9007876cde47569a533ea205403

commit 1c5e4c4984afb9007876cde47569a533ea205403
Author: Sandra Loosemore <[email protected]>
Date:   Thu May 28 15:37:11 2026 +0000

    C++, OpenMP: Handle ARRAY_TYPE array sections, not just pointers
    
    This patch is a bug fix for commit gcc-17-202-g3f8c7483112, 'OpenMP:
    Expand "declare mapper" mappers for target {enter,exit,} data
    directives'.  The ChangeLog for that patch indicated that
    cxx_omp_map_array_section was supposed to accept both arrays and
    pointers as the base expression, but the code actually only allowed
    pointers.  OTOH, both the error-checking in handle_omp_array_sections_1
    and the code generation in build_array_ref allow ARRAY_TYPE, and code with
    such expressions is actually coming in to the function.
    
    There is no test case included with this patch, but I ran across this
    in the two new test cases included with the OpenMP iterators patch
    https://gcc.gnu.org/pipermail/gcc-patches/2025-July/689071.html which
    I am preparing to resubmit.
    
    gcc/cp/ChangeLog
            * semantics.cc (cxx_omp_map_array_section): Allow ARRAY_TYPE
            expressions, not just pointers.
    
    (cherry picked from commit 12fc7c1ecd34c2e77a1ef6daefea8d16cd3106d0)

Diff:
---
 gcc/cp/semantics.cc | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index 072b5d10108f..d0a48ff85260 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -6950,9 +6950,11 @@ cxx_omp_map_array_section (location_t loc, tree t)
       if (TREE_CODE (TREE_TYPE (t)) == REFERENCE_TYPE)
 	t = convert_from_reference (t);
 
-      if (TYPE_PTR_P (TREE_TYPE (t)))
+      if (TYPE_PTR_P (TREE_TYPE (t))
+	  || TREE_CODE (TREE_TYPE (t)) == ARRAY_TYPE)
 	t = build_array_ref (loc, t, low);
       else
+	/* handle_omp_array_sections_1 has already diagnosed the error.  */
 	t = error_mark_node;
     }