[Bug target/105778] Shift by register --- unnecessary AND instruction

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105778

--- Comment #6 from Uroš Bizjak <ubizjak at gmail dot com> ---
(In reply to Jakub Jelinek from comment #4)
> It is the same thing done a few lines later in the preexisting code too.
> Shall I all of those change to gen_lowpart (QImode, force_reg (GET_MODE
> (operands[2]), operands[2])) then?

Yes, please. A "register_operand" predicate accepts SUBREGs of some strange
mode (usually FP mode) registers, and gen_lowpart chokes on these.