Instructions that use high-part QImode registers can not be encoded
with REX prefix.  To avoid REX prefix, operand constraints allow
only legacy QImode registers, immediates and constant memory operands.
The patch introduces matching predicate, so invalid operands are not
combined into instruction RTX only to be later fixed up by reload pass.

2023-02-20  Uroš Bizjak  <ubizjak@gmail.com>

gcc/ChangeLog:

    * config/i386/predicates.md
    (general_x64constmem_operand): New predicate.
    * config/i386/i386.md (*cmpqi_ext<mode>_1):
    Use nonimm_x64constmem_operand.
    (*cmpqi_ext<mode>_3): Use general_x64constmem_operand.
    (*addqi_ext<mode>_1): Ditto.
    (*testqi_ext<mode>_1): Ditto.
    (*andqi_ext<mode>_1): Ditto.
    (*andqi_ext<mode>_1_cc): Ditto.
    (*<any_or:code>qi_ext<mode>_1): Ditto.
    (*xorqi_ext<mode>_1_cc): Ditto.

Bootstrapped and regression tested on x86_64-linux-gnu {,-m32}.

Pushed to master.

Uros.