[PATCH] Fix force_nonfallthru_and_redirect

[Zdenek Dvorak]

Hello,

> > cfglayout tries to use force_nonfallthru_and_redirect to fix cases when
> > dead jumptable would emerge on fallthru edge; but
> > force_nonfallthru_and_redirect contains a special handling of jumptables
> > that does not check whether it is dead, thus making it useless.
> 
> Perhaps delete_dead_jumptables call after the cfglayout insn chain is
> constructed abd before the edges are fixed would solve this in a better
> way.
> What I was concerned about was the alive jumptables with no
> corresponding tablejump.
> I will try to test the patch.  DSo you have some testcase where current
> code fails?

I had (I will try to dig it out somewhere); IIRC bootstrap with
-fno-loop-optimize -fno-gcse -funswitch-loops failed due to this.

Zdenek