[Bug target/92953] Undesired if-conversion with overflow builtins

[amonakov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92953

--- Comment #2 from Alexander Monakov <amonakov at gcc dot gnu.org> ---
Well, the aarch64 backend does not implement subv<mode>4 pattern in the first
place, which would be required for efficient branchy code:

foo:
        subs    w0, w0, w1
        b.vc    .LBB0_2
        mvn     w0, w0
        orr     w0, w0, #0x1
.LBB0_2:
        ret

This is preferable when the branch is predictable, thanks to shorter dependency
chain.