On Tue, Jun 10, 2014 at 11:23 AM, Zhenqiang Chen wrote:
> * loop-invariant.c (struct invariant): Add a new member: eqno;
> (find_identical_invariants): Update eqno;
> (create_new_invariant): Init eqno;
> (get_inv_cost): Compute comp_cost wiht eqno;
> (gain_for_invariant): Take spill cost into account.
Look OK except ...
> @@ -1243,7 +1256,13 @@ gain_for_invariant (struct invariant *inv,
> unsigned *regs_needed,
> + IRA_LOOP_RESERVED_REGS
> - ira_class_hard_regs_num[cl];
> if (size_cost > 0)
> - return -1;
> + {
> + int spill_cost = target_spill_cost [speed] * (int) regs_needed[cl];
> + if (comp_cost <= spill_cost)
> + return -1;
> +
> + return 2;
> + }
> else
> size_cost = 0;
> }
... why "return 2", instead of just falling through to "return
comp_cost - size_cost;"?
Ciao!
Steven
