https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97137
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2020-09-21
CC| |jakub at gcc dot gnu.org,
| |uros at gcc dot gnu.org
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
ix86_carry_flag_operator can't match, because we heavily canonicalize the
comparison to GT, and so
(parallel [
(set (reg:SI 95 [ jout ])
(plus:SI (gt:SI (reg:CCFP 17 flags)
(const_int 0 [0]))
(reg:SI 100)))
(clobber (reg:CC 17 flags))
])
can't match addsi3_carry, as after conversion to integral conditions it is GEU
which requires test of two flags.
So I think we'd need instead to add patterns that would catch
(parallel [
(set (reg:SI 95 [ jout ])
(plus:SI (gt:SI (reg:DF 99)
(reg/v:DF 89 [ r2_0 ]))
(reg:SI 100)))
(clobber (reg:CC 17 flags))
])
and swap the operand order and split it back to two instructions, comparison
and and add with carry.
