Fix div by one

For k==0 the Div to Shift conversion is wrong.
Instead, we just convert to the left operand of the Div.

diff --git a/ir/ir/irarch.c b/ir/ir/irarch.c
index fc0bc22..ad1841c 100644 (file)
--- a/ir/ir/irarch.c
+++ b/ir/ir/irarch.c
@@ -951,7 +951,7 @@ ir_node *arch_dep_replace_div_by_const(ir_node *irn)
                k = tv_ld2(tv, n);
        }
 
-       if (k >= 0) { /* division by 2^k or -2^k */
+       if (k > 0) { /* division by 2^k or -2^k */
                ir_graph *irg = get_irn_irg(irn);
                if (mode_is_signed(mode)) {
                        ir_node *k_node;
@@ -990,10 +990,12 @@ ir_node *arch_dep_replace_div_by_const(ir_node *irn)
                        k_node = new_r_Const_long(irg, mode_Iu, k);
                        res    = new_rd_Shr(dbg, block, left, k_node, mode);
                }
-       } else {
+       } else if (k != 0) {
                /* other constant */
                if (allow_Mulh(params, mode))
                        res = replace_div_by_mulh(irn, tv);
+       } else { /* k == 0  i.e. division by 1 */
+               res = left;
        }
 
        if (res != irn)