fix opt/8634

[Richard Henderson]

On Tue, Apr 08, 2003 at 01:16:17AM +0200, Zdenek Dvorak wrote:
> I believe purge_addressof costs us almost nothing (I cannot be sure,
> as it has no timevar, but the fact that nobody bothered to add one
> tells something); is this really the right place where to attempt to
> save?

It's got to be about the same cost as purge_builtin_constant_p,
as both involve one linear scan of the insn stream.  Which was
identified as a definite regression in gcse times, which led to
a sequence of patches that avoided running it whenever possible.

If you added a timevar, you'd notice that you've just about
exactly doubled the amount of time spent here.



r~