extend the x % 2 CMP 0 into x % 2^n CMP 0

[r15944]

diff --git a/ir/ir/iropt.c b/ir/ir/iropt.c
index 6b8ca05..94c3bfd 100644 (file)
--- a/ir/ir/iropt.c
+++ b/ir/ir/iropt.c
@@ -3787,13 +3787,14 @@ static ir_node *transform_node_Proj_Cmp(ir_node *proj) {
                        if (is_Const(c)) {
                                tarval *tv = get_Const_tarval(c);
 
-                               if (tarval_is_long(tv) && get_tarval_long(tv) == 2) {
-                                       /* special case: (x % 2) CMP 0 ==> x & 1 CMP 0 */
+                               if (tarval_is_single_bit(tv)) {
+                                       /* special case: (x % 2^n) CMP 0 ==> x & (2^n-1) CMP 0 */
                                        ir_node *v    = get_binop_left(op);
                                        ir_node *blk  = get_irn_n(op, -1);
                                        ir_mode *mode = get_irn_mode(v);
 
-                                       left = new_rd_And(get_irn_dbg_info(op), current_ir_graph, blk, v, new_Const(mode, get_mode_one(mode)), mode);
+                                       tv = tarval_sub(tv, get_mode_one(mode));
+                                       left = new_rd_And(get_irn_dbg_info(op), current_ir_graph, blk, v, new_Const(mode, tv), mode);
                                        changed |= 1;
                                }
                        }