Sorry for being so late. I was just curious... Tom de Vries <vr...@codesourcery.com> writes: > The init cost of an iv will in general not be zero. It will be > exceptional that the iv register happens to be initialized with the > proper value at no cost. In general, there will at the very least be a > regcopy or a const set. > > 2011-05-05 Tom de Vries <t...@codesourcery.com> > > PR target/45098 > * tree-ssa-loop-ivopts.c (determine_iv_cost): Prevent > cost_base.cost == 0. > Index: gcc/tree-ssa-loop-ivopts.c > =================================================================== > --- gcc/tree-ssa-loop-ivopts.c (revision 173380) > +++ gcc/tree-ssa-loop-ivopts.c (working copy) > @@ -4688,6 +4688,8 @@ determine_iv_cost (struct ivopts_data *d > > base = cand->iv->base; > cost_base = force_var_cost (data, base, NULL); > + if (cost_base.cost == 0) > + cost_base.cost = COSTS_N_INSNS (1); > cost_step = add_cost (TYPE_MODE (TREE_TYPE (base)), data->speed); > > cost = cost_step + adjust_setup_cost (data, cost_base.cost);
...why does this reasoning apply only to this call to force_var_cost? Richard
