[Bug ada/123060] [13/14/15/16 regression] ICE in fld_incomplete_type_of when building GtkAda with LTO

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123060

--- Comment #6 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-15 branch has been updated by Eric Botcazou
<ebotcazou@gcc.gnu.org>:

https://gcc.gnu.org/g:2171c346abfc1990fdf4801e760371e64f2c75d8

commit r15-10603-g2171c346abfc1990fdf4801e760371e64f2c75d8
Author: Eric Botcazou <ebotcazou@adacore.com>
Date:   Mon Dec 15 09:09:13 2025 +0100

    Ada: Fix ICE in fld_incomplete_type_of when building GtkAda with LTO

    This is a regression from GCC 9 present on mainline and all active
branches:
    the compilation of GtkAda in LTO mode trips on the assertion present in the
    fld_incomplete_type_of function about the TYPE_CANONICAL of types pointed
to
    by pointer (or reference) types.  The problem comes from an oversight in
the
    update_pointer_to function on gcc-interface, which correctly propagates the
    TYPE_CANONICAL of the new pointer type to the old one when there is a new
    pointer type, but fails to synthesize it when there is no new pointer type.

    gcc/ada/
            PR ada/123060
            * gcc-interface/utils.cc (update_pointer_to): Synthesize a new
            TYPE_CANONICAL for the old pointer type in the case where there
            is no new pointer type.  Likewise for references.

    gcc/testsuite/
            * gnat.dg/lto30.ads, gnat.dg/lto30.adb: New test.