- Change ~(x - 1) -> -x to ~(x + -1) -> -x, because the former pattern is always...

 - Also only allow this transformation with two's complement arithmetics.

[r15883]

diff --git a/ir/ir/iropt.c b/ir/ir/iropt.c
index b3039cf..b7321df 100644 (file)
--- a/ir/ir/iropt.c
+++ b/ir/ir/iropt.c
@@ -3071,12 +3071,13 @@ static ir_node *transform_node_Eor(ir_node *n) {
  */
 static ir_node *transform_node_Not(ir_node *n) {
        ir_node *c, *oldn = n;
-       ir_node *a = get_Not_op(n);
+       ir_node *a    = get_Not_op(n);
+       ir_mode *mode = get_irn_mode(n);
 
        HANDLE_UNOP_PHI(tarval_not,a,c);
 
        /* check for a boolean Not */
-       if (get_irn_mode(n) == mode_b &&
+       if (mode == mode_b &&
                        is_Proj(a) &&
                        is_Cmp(get_Proj_pred(a))) {
                /* We negate a Cmp. The Cmp has the negated result anyways! */
@@ -3085,14 +3086,16 @@ static ir_node *transform_node_Not(ir_node *n) {
                DBG_OPT_ALGSIM0(oldn, n, FS_OPT_NOT_CMP);
                 return n;
        }
-       if (is_Sub(a)) {
-               ir_node *sub_r = get_Sub_right(a);
-               if (is_Const(sub_r) && is_Const_one(sub_r)) {
-                       /* ~(x-1) = -x */
-                       ir_node *op = get_Sub_left(a);
-                       ir_node *blk = get_irn_n(n, -1);
-                       n = new_rd_Minus(get_irn_dbg_info(n), current_ir_graph, blk, op, get_irn_mode(n));
-                       DBG_OPT_ALGSIM0(oldn, n, FS_OPT_NOT_MINUS_1);
+       if (get_mode_arithmetic(mode) == irma_twos_complement) {
+               if (is_Add(a)) {
+                       ir_node *add_r = get_Add_right(a);
+                       if (is_Const(add_r) && is_Const_all_one(add_r)) {
+                               /* ~(x + -1) = -x */
+                               ir_node *op = get_Add_left(a);
+                               ir_node *blk = get_irn_n(n, -1);
+                               n = new_rd_Minus(get_irn_dbg_info(n), current_ir_graph, blk, op, get_irn_mode(n));
+                               DBG_OPT_ALGSIM0(oldn, n, FS_OPT_NOT_MINUS_1);
+                       }
                }
        }
        return n;