Re: SSA_NAMEs not always released

[Jeffrey A Law <law at redhat dot com>]

On Wed, 2005-08-24 at 18:28 -0400, Daniel Berlin wrote:
> > If we take this after DCE, we still refer to a statement which no longer
> > exists which we don't collect in the GC.
> As i said when i pointed this out to you, we should probably skip
> walking common.chain on SSA_NAME.
> But that's non-trivial hard because it's a reused field :(
It could always be broken out, but I think we've had a few
significant changes in the compiler since the recycling code
was introduced that may push us in a completely different
direction -- namely scheduling a "cleanup" pass to recycle
unused names.

> > Could someone look into this and see what they can do?  
> 
> You should probably ask Diego or Andrew directly whether they'd like us
> to do this in bsi_remove (which requires adding an argument) and
> remove_phi_node(ditto) so that a lot less has to worry about releasing
> defs.
Like Andrew MacLeod, I'd first like to see if we can get away 
with removing the current recycling code and instead have a
pass we schedule via the pass manager which is responsible for
recycling SSA_NAME nodes.  With the changes we've made in the
last year, there's a reasonable chance this will work as good
or better than what we're doing now and it'll be more maintainable.
jeff