- if (mode_is_int(mode) && mode_is_signed(mode) &&
- get_mode_arithmetic(mode) == irma_twos_complement) {
- ir_node *x = get_Cmp_left(cmp);
-
- /* the following optimization works only with signed integer two-complement mode */
-
- if (mode == get_irn_mode(x)) {
- /*
- * FIXME: this restriction is two rigid, as it would still
- * work if mode(x) = Hs and mode == Is, but at least it removes
- * all wrong cases.
- */
- if ((pn == pn_Cmp_Lt || pn == pn_Cmp_Le) &&
- is_Const(t) && is_Const_all_one(t) &&
- is_Const(f) && is_Const_null(f)) {
- /*
- * Mux(x:T </<= 0, 0, -1) -> Shrs(x, sizeof_bits(T) - 1)
- * Conditions:
- * T must be signed.
- */
- n = new_rd_Shrs(get_irn_dbg_info(n),
- current_ir_graph, block, x,
- new_r_Const_long(current_ir_graph, block, mode_Iu,
- get_mode_size_bits(mode) - 1),
- mode);
- DBG_OPT_ALGSIM1(oldn, cmp, sel, n, FS_OPT_MUX_TO_SHR);
- return n;
- } else if ((pn == pn_Cmp_Gt || pn == pn_Cmp_Ge) &&
- is_Const(t) && is_Const_one(t) &&
- is_Const(f) && is_Const_null(f)) {
- /*
- * Mux(x:T >/>= 0, 0, 1) -> Shr(-x, sizeof_bits(T) - 1)
- * Conditions:
- * T must be signed.
- */
- n = new_rd_Shr(get_irn_dbg_info(n),
- current_ir_graph, block,
- new_r_Minus(current_ir_graph, block, x, mode),
- new_r_Const_long(current_ir_graph, block, mode_Iu,
- get_mode_size_bits(mode) - 1),
- mode);
- DBG_OPT_ALGSIM1(oldn, cmp, sel, n, FS_OPT_MUX_TO_SHR);
- return n;
- }
- }
- }