[Bug rtl-optimization/79059] Information from CCmode is not propagated across basic blocks

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79059

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I can't remember if this is the same but 

I don't know how to describe this optimization right now but take the following
two functions:
struct arc
{
  int ident;
};
int bea_is_dual_infeasible( struct arc *arc, int red_cost )
{
    return( (red_cost < 0 && arc->ident == 1)
            || (red_cost > 0 && arc->ident == 2) );
}

int bea_is_dual_infeasible1( struct arc *arc, int red_cost )
{
  int t;
  if (red_cost == 0)
    return 0;
  return arc->ident == ((red_cost > 0) ? 2 : 1);
}
They both do the same thing but bea_is_dual_infeasible1 has only one branch (no
conditional move either) while bea_is_dual_infeasible has many branches.  This
is true on x86 (have not checked arm though).