More degenerate flow graphs breaking if_convert.

[Richard Henderson]

On Mon, Jun 12, 2000 at 10:49:06AM -0600, Jeffrey A Law wrote:
> I wonder if using a more modern dead code elimination algorithm would solve
> this problem such as the one outlined in Morgan's book.  Presumably what is
> causing the problem is the cascading effect of dead code elimination and
> jump optimizations -- which I believe is handled by Morgan's dead code
> elimination algorithm.

As far as I can tell, Morgan's algorithm relies on having the
program in SSA form.  Or at least a complete use-def graph.

I'm not sure that we're ready for such a radical change.  I
think we'd be better off in the short term iterating between
calculate_global_regs_live and cleanup_cfg.


r~