i386: Fix up spaceship expanders for -mtune=i[45]86 [PR117053]

i386: Fix up spaceship expanders for -mtune=i[45]86 [PR117053]

The adjusted and new spaceship expanders ICE with -mtune=i486 or
-mtune=i586.
The problem is that in that case TARGET_ZERO_EXTEND_WITH_AND is true
and zero_extendqisi2 isn't allowed in that case, and we can't use
the replacement AND, because that clobbers flags and we want to use them
again.

The following patch fixes that by using in those cases roughly what
we want to expand it to after peephole2 optimizations, i.e. xor
before the comparison, *setcc_qi_slp and sbbl $0 (or for signed
int case xoring of 2 regs, two *setcc_qi_slp, subl).
For *setcc_qi_slp, it uses the setcc_si_slp hacks with UNSPEC that
were in use for the floating point jp case (so such code is IMHO
undesirable for the !TARGET_ZERO_EXTEND_WITH_AND case as we want to
give combiner more liberty in that case).

2024-10-11  Jakub Jelinek  <jakub@redhat.com>

	PR target/117053
	* config/i386/i386-expand.cc (ix86_expand_fp_spaceship): Handle
	TARGET_ZERO_EXTEND_WITH_AND differently.
	(ix86_expand_int_spaceship): Likewise.

	* g++.target/i386/pr116896-3.C: New test.