i386: Handle sign-extract for QImode operations with high registers [PR78952]

i386: Handle sign-extract for QImode operations with high registers [PR78952]

Introduce extract_operator predicate to handle both, zero-extract and
sign-extract extract operations with expressions like:

    (subreg:QI
      (zero_extract:SWI248
        (match_operand 1 "int248_register_operand" "0")
	(const_int 8)
	(const_int 8)) 0)

As shown in the testcase, this will enable generation of QImode
instructions with high registers when signed arguments are used.

gcc/ChangeLog:

	PR target/78952
	* config/i386/predicates.md (extract_operator): New predicate.
	* config/i386/i386.md (any_extract): Remove code iterator.
	(*cmpqi_ext<mode>_1_mem_rex64): Use extract_operator predicate.
	(*cmpqi_ext<mode>_1): Ditto.
	(*cmpqi_ext<mode>_2): Ditto.
	(*cmpqi_ext<mode>_3_mem_rex64): Ditto.
	(*cmpqi_ext<mode>_3): Ditto.
	(*cmpqi_ext<mode>_4): Ditto.
	(*extzvqi_mem_rex64): Ditto.
	(*extzvqi): Ditto.
	(*insvqi_2): Ditto.
	(*extendqi<SWI24:mode>_ext_1): Ditto.
	(*addqi_ext<mode>_0): Ditto.
	(*addqi_ext<mode>_1): Ditto.
	(*addqi_ext<mode>_2): Ditto.
	(*subqi_ext<mode>_0): Ditto.
	(*subqi_ext<mode>_2): Ditto.
	(*testqi_ext<mode>_1): Ditto.
	(*testqi_ext<mode>_2): Ditto.
	(*andqi_ext<mode>_0): Ditto.
	(*andqi_ext<mode>_1): Ditto.
	(*andqi_ext<mode>_1_cc): Ditto.
	(*andqi_ext<mode>_2): Ditto.
	(*<any_or:code>qi_ext<mode>_0): Ditto.
	(*<any_or:code>qi_ext<mode>_1): Ditto.
	(*<any_or:code>qi_ext<mode>_2): Ditto.
	(*xorqi_ext<mode>_1_cc): Ditto.
	(*negqi_ext<mode>_2): Ditto.
	(*ashlqi_ext<mode>_2): Ditto.
	(*<any_shiftrt:insn>qi_ext<mode>_2): Ditto.

gcc/testsuite/ChangeLog:

	PR target/78952
	* gcc.target/i386/pr78952-4.c: New test.