i386: Use QImode for offsets in zero_extract/sign_extract in i386.md

i386: Use QImode for offsets in zero_extract/sign_extract in i386.md

As suggested by Uros, this patch changes the ZERO_EXTRACTs and SIGN_EXTRACTs
in i386.md to consistently use QImode for bit offsets (i.e. third and fourth
operands), matching the use of QImode for bit counts in shifts and rotates.

There's no change in functionality, and the new patterns simply ensure that
we continue to generate the same code (match revised patterns) as before.

2023-07-22  Roger Sayle  <roger@nextmovesoftware.com>

gcc/ChangeLog
	* config/i386/i386.md (extv<mode>): Use QImode for offsets.
	(extzv<mode>): Likewise.
	(insv<mode>): Likewise.
	(*testqi_ext_3): Likewise.
	(*btr<mode>_2): Likewise.
	(define_split): Likewise.
	(*btsq_imm): Likewise.
	(*btrq_imm): Likewise.
	(*btcq_imm): Likewise.
	(define_peephole2 x3): Likewise.
	(*bt<mode>): Likewise
	(*bt<mode>_mask): New define_insn_and_split.
	(*jcc_bt<mode>): Use QImode for offsets.
	(*jcc_bt<mode>_1): Delete obsolete pattern.
	(*jcc_bt<mode>_mask): Use QImode offsets.
	(*jcc_bt<mode>_mask_1): Likewise.
	(define_split): Likewise.
	(*bt<mode>_setcqi): Likewise.
	(*bt<mode>_setncqi): Likewise.
	(*bt<mode>_setnc<mode>): Likewise.
	(*bt<mode>_setncqi_2): Likewise.
	(*bt<mode>_setc<mode>_mask): New define_insn_and_split.
	(bmi2_bzhi_<mode>3): Use QImode offsets.
	(*bmi2_bzhi_<mode>3): Likewise.
	(*bmi2_bzhi_<mode>3_1): Likewise.
	(*bmi2_bzhi_<mode>3_1_ccz): Likewise.
	(@tbm_bextri_<mode>): Likewise.