Ping.
The patch has been committed to trunk 2 months ago.
Okay for committing to GCC15 now?
thanks.
Qing
> On Jul 17, 2025, at 17:26, Qing Zhao <qing.z...@oracle.com> wrote:
>
> There is only one last_field for a structure type, but there might
> be multiple last_fields for a union type, therefore we should ORed
> the result of TYPE_INCLUDES_FLEXARRAY for multiple last_fields of
> a union type.
>
> PR c/120354
>
> gcc/c/ChangeLog:
>
> * c-decl.cc (finish_struct): Or the results for TYPE_INCLUDES_FLEXARRAY.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/pr120354.c: New test.
>
> (cherry picked from commit 70418e6c0120cfce33ab69628602dfdadbed683a)
>
> Bootstrapped and regression tested on both X86 and aarch64.
> Okay for backporting to GCC15?
>
> thanks.
>
> Qing
> ---
> gcc/c/c-decl.cc | 9 ++++++---
> gcc/testsuite/gcc.dg/pr120354.c | 33 +++++++++++++++++++++++++++++++++
> 2 files changed, 39 insertions(+), 3 deletions(-)
> create mode 100644 gcc/testsuite/gcc.dg/pr120354.c
>
> diff --git a/gcc/c/c-decl.cc b/gcc/c/c-decl.cc
> index 42e17dcdbf8..5032ba13779 100644
> --- a/gcc/c/c-decl.cc
> +++ b/gcc/c/c-decl.cc
> @@ -9665,15 +9665,18 @@ finish_struct (location_t loc, tree t, tree
> fieldlist, tree attributes,
> DECL_NOT_FLEXARRAY (x) = !is_flexible_array_member_p (is_last_field, x);
>
> /* Set TYPE_INCLUDES_FLEXARRAY for the context of x, t.
> - when x is an array and is the last field. */
> + when x is an array and is the last field.
> + There is only one last_field for a structure type, but there might
> + be multiple last_fields for a union type, therefore we should ORed
> + the result for multiple last_fields. */
> if (TREE_CODE (TREE_TYPE (x)) == ARRAY_TYPE)
> TYPE_INCLUDES_FLEXARRAY (t)
> - = is_last_field && c_flexible_array_member_type_p (TREE_TYPE (x));
> + |= is_last_field && c_flexible_array_member_type_p (TREE_TYPE (x));
> /* Recursively set TYPE_INCLUDES_FLEXARRAY for the context of x, t
> when x is an union or record and is the last field. */
> else if (RECORD_OR_UNION_TYPE_P (TREE_TYPE (x)))
> TYPE_INCLUDES_FLEXARRAY (t)
> - = is_last_field && TYPE_INCLUDES_FLEXARRAY (TREE_TYPE (x));
> + |= is_last_field && TYPE_INCLUDES_FLEXARRAY (TREE_TYPE (x));
>
> if (warn_flex_array_member_not_at_end
> && !is_last_field
> diff --git a/gcc/testsuite/gcc.dg/pr120354.c b/gcc/testsuite/gcc.dg/pr120354.c
> new file mode 100644
> index 00000000000..6749737a173
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/pr120354.c
> @@ -0,0 +1,33 @@
> +/* PR120354: Test for -Wflex-array-member-not-at-end on union with
> + flexible array members. */
> +/* { dg-do compile } */
> +/* { dg-options "-Wflex-array-member-not-at-end" } */
> +
> +struct P {};
> +union L {};
> +
> +union X {
> + int x[];
> + struct P y;
> +};
> +
> +struct T {
> + union X x; /* { dg-warning "structure containing a flexible array member
> is not at the end of another structure" } */
> + int plug;
> +};
> +
> +struct Q {
> + int len;
> + int data[];
> +};
> +
> +union Y {
> + struct Q q;
> + union L y;
> +};
> +
> +struct S {
> + union Y y; /* { dg-warning "structure containing a flexible array
> member is not at the end of another structure" } */
> + int plug;
> +};
> +
> --
> 2.31.1
>
