[Bug c++/68252] regiression left operand of shift expression, while we shift > 0 integer

[glisse at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68252

--- Comment #2 from Marc Glisse <glisse at gcc dot gnu.org> ---
(with { tree utype = unsigned_type_for (TREE_TYPE (@0)); }
 (convert (lshift (convert:utype @0) @2))))
maybe?