[Bug middle-end/105533] UBSAN: gcc/expmed.cc:3272:26: runtime error: signed integer overflow: -9223372036854775808 - 1 cannot be represented in type 'long int'

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105533

--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
The same function already does
offset += pop->off * BITS_PER_UNIT;
a few lines earlier, so I think doing it here is fine as well.
Or yet another option is to cast pop->off or op->off to offset_int first and do
the
left shift in offset_int type where it is well defined.
2024-03-06  Jakub Jelinek  <jakub@redhat.com>

        PR middle-end/105533
        * tree-ssa-sccvn.cc (ao_ref_init_from_vn_reference) <case ARRAY_REF>:
        Multiple op->off by BITS_PER_UNIT instead of shifting it left by
        LOG2_BITS_PER_UNIT.

--- gcc/tree-ssa-sccvn.cc.jj    2024-02-28 22:57:18.318658827 +0100
+++ gcc/tree-ssa-sccvn.cc       2024-03-06 14:52:16.819229719 +0100
@@ -1221,7 +1221,7 @@ ao_ref_init_from_vn_reference (ao_ref *r
          if (maybe_eq (op->off, -1))
            max_size = -1;
          else
-           offset += op->off << LOG2_BITS_PER_UNIT;
+           offset += op->off * BITS_PER_UNIT;
          break;

        case REALPART_EXPR: