https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103216
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
For x86_64 we might be able to solve this at the RTL level during combine:
(set (reg/v:QI 84 [ <retval> ])
(if_then_else:QI (lt (subreg:QI (reg:SI 86 [ a ]) 0)
(const_int 0 [0]))
(ior:QI (subreg:QI (reg:SI 86 [ a ]) 0)
(const_int -128 [0xffffffffffffff80]))
(reg/v:QI 84 [ <retval> ])))
That is optimize:
(a < 0) ? a | signbit : b
to
(a < 0) ? a : b
And I suspect we need after that)
(a < 0) ? a : a & ~signbit
into:
a
