On Fri, Aug 8, 2025 at 10:13 AM Stefan Schulze Frielinghaus
<stefa...@linux.ibm.com> wrote:
>
> From: Stefan Schulze Frielinghaus <stefa...@gcc.gnu.org>
>
> In case an asm operand is an error node, constraints etc. are still
> validated. Furthermore, all other operands are gimplified, although an
> error is returned in the end anyway. For hard register constraints an
> operand is required in order to determine the mode from which the number
> of registers follows. Therefore, I could simply guard hard register
> constraints checking or bailing out early. The former would mean extra
> error node checks where we already have a few, and the latter would
> reduce the amount of those checks but would also mean that we report
> potentially fewer errors during a single run. Is there any preference?
> It seems to me that bailing out as late as possible was desired but I
> might be wrong here.
I think bailing out early isn't a problem, so I'd do whatever is minimal here
to avoid ICEs on already diagnosed invalid code
Richard.
> ---
> gcc/gimplify.cc | 4 ++++
> gcc/testsuite/gcc.dg/pr121391.c | 9 +++++++++
> 2 files changed, 13 insertions(+)
> create mode 100644 gcc/testsuite/gcc.dg/pr121391.c
>
> diff --git a/gcc/gimplify.cc b/gcc/gimplify.cc
> index ca1fa2189cb..2b790923fa1 100644
> --- a/gcc/gimplify.cc
> +++ b/gcc/gimplify.cc
> @@ -7930,6 +7930,8 @@ gimplify_asm_expr (tree *expr_p, gimple_seq *pre_p,
> gimple_seq *post_p)
> bool ok;
> size_t constraint_len;
>
> + if (TREE_VALUE (link) == error_mark_node)
> + return GS_ERROR;
> link_next = TREE_CHAIN (link);
>
> oconstraints[i]
> @@ -8155,6 +8157,8 @@ gimplify_asm_expr (tree *expr_p, gimple_seq *pre_p,
> gimple_seq *post_p)
> int input_num = 0;
> for (link = ASM_INPUTS (expr); link; ++input_num, ++i, link = link_next)
> {
> + if (TREE_VALUE (link) == error_mark_node)
> + return GS_ERROR;
> link_next = TREE_CHAIN (link);
> constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
> reg_info.operand = TREE_VALUE (link);
> diff --git a/gcc/testsuite/gcc.dg/pr121391.c b/gcc/testsuite/gcc.dg/pr121391.c
> new file mode 100644
> index 00000000000..caffa854a9a
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/pr121391.c
> @@ -0,0 +1,9 @@
> +/* { dg-compile { target aarch64*-*-* arm*-*-* powerpc*-*-* s390*-*-*
> x86_64-*-* } */
> +
> +/* For the non existing variable we are faced with an error mark node during
> + gimplify_asm_expr(). */
> +
> +void test (void)
> +{
> + __asm__ __volatile__ ("" :: "{2}" (non_existing_var));
> +}
> --
> 2.49.0
>
