[Bug target/106101] [12/13 Regression] ICE in reg_bitfield_target_p since r12-4428-g147ed0184f403b

["cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106101

--- Comment #20 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Andreas Krebbel <krebbel@gcc.gnu.org>:

https://gcc.gnu.org/g:585a21bab3ec688c2039bff2922cc372d8558283

commit r13-2201-g585a21bab3ec688c2039bff2922cc372d8558283
Author: Andreas Krebbel <krebbel@linux.ibm.com>
Date:   Fri Jul 29 09:55:54 2022 +0200

    PR 106101: IBM zSystems: Fix strict_low_part problem

    This avoids generating illegal (strict_low_part (reg ...)) RTXs. This
    required two changes:

    1. Do not use gen_lowpart to generate the inner expression of a
    STRICT_LOW_PART.  gen_lowpart might fold the SUBREG either because
    there is already a paradoxical subreg or because it can directly be
    applied to the register. A new wrapper function makes sure that we
    always end up having an actual SUBREG.

    2. Change the movstrict patterns to enforce a SUBREG as inner operand
    of the STRICT_LOW_PARTs.  The new predicate introduced for the
    destination operand requires a SUBREG expression with a
    register_operand as inner operand.  However, since reload strips away
    the majority of the SUBREGs we have to accept single registers as well
    once we reach reload.

    Bootstrapped and regression tested on IBM zSystems 64 bit.

    gcc/ChangeLog:

            PR target/106101
            * config/s390/predicates.md (subreg_register_operand): New
            predicate.
            * config/s390/s390-protos.h (s390_gen_lowpart_subreg): New
            function prototype.
            * config/s390/s390.cc (s390_gen_lowpart_subreg): New function.
            (s390_expand_insv): Use s390_gen_lowpart_subreg instead of
            gen_lowpart.
            * config/s390/s390.md ("*get_tp_64", "*zero_extendhisi2_31")
            ("*zero_extendqisi2_31", "*zero_extendqihi2_31"): Likewise.
            ("movstrictqi", "movstricthi", "movstrictsi"): Use the
            subreg_register_operand predicate instead of register_operand.

    gcc/testsuite/ChangeLog:

            PR target/106101
            * gcc.c-torture/compile/pr106101.c: New test.