https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97873
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Target| |x86_64-*-* i?86-*-*
Status|UNCONFIRMED |NEW
Component|tree-optimization |target
Last reconfirmed| |2020-11-17
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
We're expanding from
_2 = ABS_EXPR <x_1(D)>;
return _2;
that's nothing to improve on the GIMPLE level. x86 has an abs expander
that might or might not trigger (it doesn't look like for generic).
We expand as
insn 6 3 7 2 (parallel [
(set (reg:SI 85)
(neg:SI (reg/v:SI 83 [ x ])))
(clobber (reg:CC 17 flags))
]) "t.i":3:29 -1
(nil))
(insn 7 6 8 2 (parallel [
(set (reg:SI 84)
(smax:SI (reg/v:SI 83 [ x ])
(reg:SI 85)))
(clobber (reg:CC 17 flags))
]) "t.i":3:29 -1
(nil))
(insn 8 7 12 2 (set (reg:SI 82 [ <retval> ])
(reg:SI 84)) "t.i":3:29 -1
(nil))
(insn 12 8 13 2 (set (reg/i:SI 0 ax)
(reg:SI 82 [ <retval> ])) "t.i":4:1 -1
(nil))
where the smax:SI is late splitted IIRC. That's probably not the optimal
expansion choice.
I remember a duplicate bug.
