i386: Use SDWIM mode iterator for abs and maxmin [PR97873]

i386: Use SDWIM mode iterator for abs and maxmin [PR97873]

Generate special double mode sequence also for QImode and HImode.

Without QImode and HImode patterns, middle-end extends operands to SImode
and emits SImode conditional move instruction with paradoxical SImode output
register.  This form is not recognized by STV pass, but a single abs with
input operand in a register would not be converted anyway due to relatively
high register conversion cost.

2020-11-26  Uroš Bizjak  <ubizjak@gmail.com>

	PR target/97873

gcc/
	* config/i386/i386.md (abs<mode>2): Use SDWIM mode iterator.
	(*abs<mode>2_1): Use SWI mode iterator.

	(<maxmin:code><mode>3): Use SDWIM mode iterator.
	(*<maxmin:code><mode>3_1): Use SWI mode iterator.

gcc/testsuite/
	* gcc.target/i386/pr97873-3.c: New test.