[Bug middle-end/104558] [9/10/11/12 Regression] ICE: in expand_call, at calls.cc:3601 with -fabi-version=9 on pr83487.c

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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104558

--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:e6e6e0a97340068c90fe091482efbaacd6474754

commit r12-7458-ge6e6e0a97340068c90fe091482efbaacd6474754
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Thu Mar 3 09:11:09 2022 +0100

    calls: When bypassing emit_push_insn for 0 sized arg, emit at least
anti_adjust_stack for alignment pad if needed [PR104558]

    The following testcase ICEs on x86_64 when asked to use the pre-GCC 8
    ABI where zero sized arguments weren't ignored.
    In GCC 7 the emit_push_insn calls in store_one_arg were unconditional,
    it is true that they didn't actually push anything because it had zero
    size, but because arg->locate.alignment_pad is 8 in this case,
    emit_push_insn at the end performs
              if (alignment_pad && args_addr == 0)
                anti_adjust_stack (alignment_pad);
    and an assert larger on is upset if we don't do it.
    The following patch keeps the emit_push_insn conditional but calls
    the anti_adjust_stack when needed by hand for the zero sized arguments.
    For the new x86_64 ABI where zero sized arguments are ignored
    arg->locate.alignment_pad is 0 in this case, so nothing changes
    - we in that case really do ignore it.

    There is another emit_push_insn call earlier in store_one_arg, also made
    conditional on non-zero size by Marek in GCC 8, but that one is for
    arguments with non-BLKmode and the only way those can be zero size is
    if they are TYPE_EMPTY_P aka when they are completely ignored.  But
    I believe arg->locate.alignment_pad should be 0 in that case, so IMHO
    there is no need to do anything in the second spot.

    2022-03-03  Jakub Jelinek  <jakub@redhat.com>

            PR middle-end/104558
            * calls.cc (store_one_arg): When not calling emit_push_insn
            because size_rtx is const0_rtx, call at least anti_adjust_stack
            on arg->locate.alignment_pad if !argblock and the alignment might
            be non-zero.

            * gcc.dg/pr104558.c: New test.