[tree-ssa][ GC, Virtual operands, and GCing between passes

[Geoff Keating]

Andrew MacLeod <amacleod@redhat.com> writes:

> Are we sure we want to GC between passes? :-|
> 
> since VDEFs and VUSEs are tree nodes, I can't allocate the structure
> which holds them anywhere except GC'd memory can I?
> 
> ie
> 
> a_3 = VDEF <a_2>
> 
> This requires points to 2 trees.
> 
> the GC system has to know not to collect the trees I am pointing to in
> the 2 words of the vdef vector.
> 
> but I dont want to GC the vdef vector.

Why not?

-- 
- Geoffrey Keating <geoffk@geoffk.org>