http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52868
--- Comment #1 from Igor Zamyatin <izamyatin at gmail dot com> 2012-04-19
13:09:07 UTC ---
Experimental patch that fixes the regression:
diff --git a/gcc/tree-ssa-loop-ivopts.c b/gcc/tree-ssa-loop-ivopts.c
index 3c11c0e..9c04516 100644
--- a/gcc/tree-ssa-loop-ivopts.c
+++ b/gcc/tree-ssa-loop-ivopts.c
@@ -4112,6 +4112,7 @@ get_computation_cost_at (struct ivopts_data *data,
else if (ratio == 1)
{
tree real_cbase = cbase;
+ int diff_cost, add_cost_val;
/* Check to see if any adjustment is needed. */
if (cstepi == 0 && stmt_is_after_inc)
@@ -4131,7 +4132,19 @@ get_computation_cost_at (struct ivopts_data *data,
ubase, real_cbase,
&symbol_present, &var_present, &offset,
depends_on);
+ diff_cost = cost.cost;
cost.cost /= avg_loop_niter (data->current_loop);
+ add_cost_val = add_cost (TYPE_MODE (ctype), data->speed);
+ /* do cost correction if address cost is small enough
+ and difference cost is high enough */
+ if (address_p && diff_cost > add_cost_val
+ && get_address_cost (symbol_present, var_present,
+ offset, ratio, cstepi,
+ TYPE_MODE (TREE_TYPE (utype)),
+ TYPE_ADDR_SPACE (TREE_TYPE (utype)),
+ speed, stmt_is_after_inc,
+ can_autoinc).cost <= add_cost_val)
+ cost.cost += add_cost_val;
}
else if (address_p
&& !POINTER_TYPE_P (ctype)
It also fixes the bwaves regression from
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52272
