Sorry, I'm find this a bit tough to review. Could you provide some
overview comments somewhere to say what the new algorithm is?
The comment at the head of regrename.c still describes the current
bb-local algorithm.
One thing though:
Bernd Schmidt <ber...@codesourcery.com> writes:
> @@ -215,8 +306,9 @@ merge_overlapping_regs (HARD_REG_SET *ps
> IOR_HARD_REG_SET (*pset, head->hard_conflicts);
> EXECUTE_IF_SET_IN_BITMAP (&head->conflicts, 0, i, bi)
> {
> - du_head_p other = VEC_index (du_head_p, id_to_chain, i);
> + du_head_p other = chain_from_id (i);
> unsigned j = other->nregs;
> + gcc_assert (other != head);
> while (j-- > 0)
> SET_HARD_REG_BIT (*pset, other->regno + j);
> }
Is this effectively cubic in the number of chains? There are O(chains)
calls to merge_overlapping_regs, O(chains) nodes in the conflicts bitmap,
and chain_from_id chases O(chains) merges.
I realise this probably isn't a problem in practice. Just looking
for reassurance. :-)
Richard
