+/* If possible, adds autoincrement candidates BASE + STEP * i based on use USE.
+ Important field is set to IMPORTANT. */
+
+static void
+add_autoinc_candidates (struct ivopts_data *data, tree base, tree step,
+ bool important, struct iv_use *use)
+{
+ basic_block use_bb = gimple_bb (use->stmt);
+ enum machine_mode mem_mode;
+ unsigned HOST_WIDE_INT cstepi;
+
+ /* If we insert the increment in any position other than the standard
+ ones, we must ensure that it is incremented once per iteration.
+ It must not be in an inner nested loop, or one side of an if
+ statement. */
+ if (use_bb->loop_father != data->current_loop
+ || !dominated_by_p (CDI_DOMINATORS, data->current_loop->latch, use_bb)
+ || stmt_could_throw_p (use->stmt)
+ || !cst_and_fits_in_hwi (step))
+ return;
+
+ cstepi = int_cst_value (step);
+
+ mem_mode = TYPE_MODE (TREE_TYPE (*use->op_p));
+ if ((HAVE_PRE_INCREMENT && GET_MODE_SIZE (mem_mode) == cstepi)
+ || (HAVE_PRE_DECREMENT && GET_MODE_SIZE (mem_mode) == -cstepi))
+ {
+ enum tree_code code = MINUS_EXPR;
+ tree new_base;
+ tree new_step = step;
+
+ if (POINTER_TYPE_P (TREE_TYPE (base)))
+ {
+ new_step = fold_build1 (NEGATE_EXPR, TREE_TYPE (step), step);
+ code = POINTER_PLUS_EXPR;
+ }
+ else
+ new_step = fold_convert (TREE_TYPE (base), new_step);
+ new_base = fold_build2 (code, TREE_TYPE (base), base, new_step);
+ add_candidate_1 (data, new_base, step, important, IP_BEFORE_USE, use,
+ use->stmt);
+ }
+ if ((HAVE_POST_INCREMENT && GET_MODE_SIZE (mem_mode) == cstepi)
+ || (HAVE_POST_DECREMENT && GET_MODE_SIZE (mem_mode) == -cstepi))
+ {
+ add_candidate_1 (data, base, step, important, IP_AFTER_USE, use,
+ use->stmt);
+ }
+}
+