[Bug tree-optimization/77820] A jump threading opportunity with conditionals

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77820

--- Comment #2 from Segher Boessenkool <segher at gcc dot gnu.org> ---
Note that combine cannot optimise the

        cset    w0, lt
        cbnz    w0, .L6

to

        blt     .L6

because the two insns are in different BBs still.  The final branch
isn't duplicated until bb-reorder.  (The two scc's use the same pseudo
as well).

This should be handled before expand imho.