[Bug target/112454] csinc (csel is though) is not being used when there is matches twice

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112454

--- Comment #5 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The trunk branch has been updated by Andrew Pinski <pinskia@gcc.gnu.org>:

https://gcc.gnu.org/g:d29d27bde5df89e5357e0a33a71bb49125bd1655

commit r14-5893-gd29d27bde5df89e5357e0a33a71bb49125bd1655
Author: Andrew Pinski <quic_apinski@quicinc.com>
Date:   Sun Nov 26 23:25:51 2023 +0000

    aarch64: Improve cost of `a ? {-,}1 : b`

    While looking into PR 112454, I found the cost for
    `(if_then_else (cmp) (const_int 1) (reg))` was being recorded as 8
    (or `COSTS_N_INSNS (2)`) but it should have been 4 (or `COSTS_N_INSNS
(1)`).
    This improves the cost by not adding the cost of `(const_int 1)` to
    the total cost.

    It does not does not fully fix PR 112454 as that requires other changes to
forwprop
    the `(const_int 1)` earlier than combine. Though we do fix the loop case
where the
    constant was only used once.

    Bootstrapped and tested on aarch64-linux-gnu with no regressions.

    gcc/ChangeLog:

            * config/aarch64/aarch64.cc (aarch64_if_then_else_costs):
            Handle csinv/csinc case of 1/-1.

    gcc/testsuite/ChangeLog:

            * gcc.target/aarch64/csinc-3.c: New test.

    Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>