From mboxrd@z Thu Jan  1 00:00:00 1970
From: Richard Henderson <rth@cygnus.com>
To: Joe Buck <jbuck@synopsys.com>
Cc: rth@cygnus.com, egcs@cygnus.com
Subject: Re: switch index optimization
Date: Sun, 25 Jan 1998 23:14:00 -0000
Message-id: <19980125231458.46648@dot.cygnus.com>
References: <19980125223511.42443@dot.cygnus.com> <199801260701.XAA10048@atrus.synopsys.com>
X-SW-Source: 1998-01/msg00917.html

On Sun, Jan 25, 1998 at 11:01:48PM -0800, Joe Buck wrote:
> Not a bad idea, but kind of an unclean implementation.

Guilty.

> But to do really well, range propagation needs to be done with dataflow
> analysis (though in this case you can do it without).

Thus my comment about maybe doing it in jump.  It does some of
that sort of thing, and I am half-remembering Jeff doing some
work recently in that area for <censored>, such that

	if (x < 7) {
		if (x == 9) { }
	}

and similar get optimized properly.

Ah well, perhaps I'll clean up what I was doing, and if someone does
do the Right Thing elsewhere later, we can strip mine back out.


r~