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

[S. Bosscher]

> The problem is that gengtype will not allow me to have vevotrs of type
> tree **. It says its an unknown type.
> 
> typedef struct def_optype_d GTY(())
> {
>   unsigned num_defs;
>   tree ** defs;
> } def_optype_t;

Try this with http://gcc.gnu.org/ml/gcc-patches/2003-12/msg00593.html.

If that doesn't work, make it "PTR * GTY((skip ())) defs" (or just
"void **" if you have that patch applied anyway) and cast to tree
where needed.

Gr.
Steven