-
-/* Replace DivMods with Shifts and Add/Subs and Mulh. */
-void arch_dep_replace_divmod_by_const(ir_node **div, ir_node **mod, ir_node *irn)
-{
- *div = *mod = NULL;
-
- /* If the architecture dependent optimizations were not initialized
- or this optimization was not enabled. */
- if (params == NULL ||
- ((opts & (arch_dep_div_by_const|arch_dep_mod_by_const)) != (arch_dep_div_by_const|arch_dep_mod_by_const)))
- return;
-
- if (is_DivMod(irn)) {
- ir_node *c = get_DivMod_right(irn);
- ir_node *block, *left;
- ir_mode *mode;
- tarval *tv, *ntv;
- dbg_info *dbg;
- int n, bits;
- int k;
- int n_flag = 0;
-
- if (! is_Const(c))
- return;
-
- tv = get_Const_tarval(c);
-
- /* check for division by zero */
- if (tarval_is_null(tv))
- return;
-
- left = get_DivMod_left(irn);
- mode = get_irn_mode(left);
- block = get_irn_n(irn, -1);
- dbg = get_irn_dbg_info(irn);
-
- bits = get_mode_size_bits(mode);
- n = (bits + 7) / 8;
-
- k = -1;
- if (mode_is_signed(mode)) {
- /* for signed divisions, the algorithm works for a / -2^k by negating the result */
- ntv = tarval_neg(tv);
- n_flag = 1;
- k = tv_ld2(ntv, n);
- }
-
- if (k < 0) {
- n_flag = 0;
- k = tv_ld2(tv, n);
- }
-
- if (k >= 0) { /* division by 2^k or -2^k */
- if (mode_is_signed(mode)) {
- ir_node *k_node, *c_k;
- ir_node *curr = left;
-
- if (k != 1) {
- k_node = new_Const_long(mode_Iu, k - 1);
- curr = new_rd_Shrs(dbg, block, left, k_node, mode);
- }
-
- k_node = new_Const_long(mode_Iu, bits - k);
- curr = new_rd_Shr(dbg, block, curr, k_node, mode);
-
- curr = new_rd_Add(dbg, block, left, curr, mode);
-
- c_k = new_Const_long(mode_Iu, k);
-
- *div = new_rd_Shrs(dbg, block, curr, c_k, mode);
-
- if (n_flag) { /* negate the div result */
- ir_node *k_node;
-
- k_node = new_Const(get_mode_null(mode));
- *div = new_rd_Sub(dbg, block, k_node, *div, mode);
- }
-
- k_node = new_Const_long(mode, (-1) << k);
- curr = new_rd_And(dbg, block, curr, k_node, mode);
-
- *mod = new_rd_Sub(dbg, block, left, curr, mode);
- } else { /* unsigned case */
- ir_node *k_node;
-
- k_node = new_Const_long(mode_Iu, k);
- *div = new_rd_Shr(dbg, block, left, k_node, mode);
-
- k_node = new_Const_long(mode, (1 << k) - 1);
- *mod = new_rd_And(dbg, block, left, k_node, mode);
- }
- } else {
- /* other constant */
- if (allow_Mulh(mode)) {
- ir_node *t;
-
- *div = replace_div_by_mulh(irn, tv);
-
- t = new_rd_Mul(dbg, block, *div, c, mode);
-
- /* t = arch_dep_mul_to_shift(t); */
-
- *mod = new_rd_Sub(dbg, block, left, t, mode);
- }
- }
- }
-
- if (*div)
- hook_arch_dep_replace_division_by_const(irn);
-}
-
-
-static const ir_settings_arch_dep_t default_params = {
- 1, /* also use subs */
- 4, /* maximum shifts */
- 31, /* maximum shift amount */
- default_evaluate, /* default evaluator */
-
- 0, /* allow Mulhs */
- 0, /* allow Mulus */
- 32 /* Mulh allowed up to 32 bit */
-};
-
-/* A default parameter factory for testing purposes. */
-const ir_settings_arch_dep_t *arch_dep_default_factory(void)
-{
- return &default_params;
-}