Hi! I'm looking at tree-ssa-threadbackward.c, where we pass around a lot of "vec<basic_block, va_gc>" pointers representing a path through a flow graph.
I'm wondering why we use va_gc, when AFAICT, the paths are local to the pass, and we can easily free them with path.release() at the end of the pass. For that matter, it seems like we're already going through the trouble of freeing them manually: vec<basic_block, va_gc> *bb_path; vec_alloc (bb_path, 10); ... vec_free (bb_path); Am I missing something wrt vl_embed and vl_ptr magic, or would it be acceptable to replace all these vec<basic_block, va_gc> with vec<basic_block> and use the stack? First because the GC has additional overhead, and second because vec<TYPE, va_gc> is fugly. If so, I'm assuming that similar things can be done throughout the compiler. Why use GC, when a vector is local to a pass? Thanks. Aldy
