[Bug tree-optimization/113462] ICE: in handle_cast, at gimple-lower-bitint.cc:1539 at -O with _BitInt() in a struct

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113462

--- Comment #5 from GCC 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:5015015ae6b29b3f1734c7693ba25b88cdd531a1

commit r14-8349-g5015015ae6b29b3f1734c7693ba25b88cdd531a1
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Tue Jan 23 09:02:48 2024 +0100

    fold-const: Fold larger VIEW_CONVERT_EXPRs [PR113462]

    On Mon, Jan 22, 2024 at 11:27:52AM +0100, Richard Biener wrote:
    > We run into
    >
    > static tree
    > native_interpret_int (tree type, const unsigned char *ptr, int len)
    > {
    > ...
    >   if (total_bytes > len
    >       || total_bytes * BITS_PER_UNIT > HOST_BITS_PER_DOUBLE_INT)
    >     return NULL_TREE;
    >
    > OTOH using a V_C_E to "truncate" a _BitInt looks wrong?  OTOH the
    > check doesn't really handle native_encode_expr using the "proper"
    > wide_int encoding however that's exactly handled.  So it might be
    > a pre-existing issue that's only uncovered by large _BitInts
    > (__int128 might show similar issues?)

    I guess the || total_bytes * BITS_PER_UNIT > HOST_BITS_PER_DOUBLE_INT
    conditions make no sense, all we care is whether it fits in the buffer
    or not.
    But then there is
    fold_view_convert_expr
    (and other spots) which use
      /* We support up to 1024-bit values (for GCN/RISC-V V128QImode).  */
      unsigned char buffer[128];
    or something similar.
    This patch fixes even that by using a XALLOCAVEC allocated buffer
    if the type size is 129 .. 8192 bytes.

    2024-01-22  Jakub Jelinek  <jakub@redhat.com>

            PR tree-optimization/113462
            * fold-const.cc (native_interpret_int): Don't punt if total_bytes
            is larger than HOST_BITS_PER_DOUBLE_INT / BITS_PER_UNIT.
            (fold_view_convert_expr): Use XALLOCAVEC buffers for types with
            sizes between 129 and 8192 bytes.