[Bug fortran/124450] [16 Regression] trans-io.cc:2516: runtime error

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124450

--- Comment #9 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-13 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:f82124516c3e605ebd4b492a000d02da38ab3bfe

commit r13-10216-gf82124516c3e605ebd4b492a000d02da38ab3bfe
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Thu Mar 12 12:39:43 2026 +0100

    fortran: Fix UB in transfer_expr [PR124450]

    trans-io.cc (transfer_array_component) calls transfer_expr with
    NULL code:
      transfer_expr (&se, &cm->ts, tmp, NULL, NULL_TREE);
    I'm surprised it doesn't ICE in other spots that dereference
    code->whatever but each one is guarded with some condition
    that perhaps don't trigger in that case for some reason.
    Anyway, the &code->loc case does trigger, it doesn't ICE, but
    it is undefined behavior in the compiler when code is NULL,
    and we'd crash if the where argument of 3*sizeof(void*) is
    dereferenced.  Code I've checked can handle NULL where though.

    2026-03-12  Jakub Jelinek  <jakub@redhat.com>

            PR fortran/124450
            * trans-io.cc (transfer_expr): If code is NULL, call
            transfer_array_component with NULL where argument rather than
            &code->loc.

            * gfortran.dg/pr124450.f90: New test.

    (cherry picked from commit adefcfed81e19aa250f34914182a7c5580dc6e2a)