implement load after store for different modes in big endian

diff --git a/ir/opt/ldstopt.c b/ir/opt/ldstopt.c
index c1098e2..f40db3d 100644 (file)
--- a/ir/opt/ldstopt.c
+++ b/ir/opt/ldstopt.c
@@ -707,32 +707,28 @@ static int try_load_after_store(ir_node *load,
        delta          = load_offset - store_offset;
        store_value    = get_Store_value(store);
 
-       if (delta != 0 || store_mode != load_mode) {
-               /* TODO: implement for big-endian */
-               if (delta < 0 || delta + load_mode_len > store_mode_len
-                               || (be_get_backend_param()->byte_order_big_endian
-                                   && load_mode_len != store_mode_len))
-                       return 0;
-
-               if (get_mode_arithmetic(store_mode) != irma_twos_complement ||
-                       get_mode_arithmetic(load_mode)  != irma_twos_complement)
-                       return 0;
+       if (delta < 0 || delta+load_mode_len > store_mode_len)
+               return 0;
 
+       if (store_mode != load_mode &&
+           get_mode_arithmetic(store_mode) == irma_twos_complement &&
+           get_mode_arithmetic(load_mode)  == irma_twos_complement) {
 
                /* produce a shift to adjust offset delta */
-               if (delta > 0) {
-                       ir_node *cnst;
-                       ir_graph *irg = get_irn_irg(load);
-
-                       cnst        = new_r_Const_long(irg, mode_Iu, delta * 8);
+               unsigned const shift = be_get_backend_param()->byte_order_big_endian
+                       ? store_mode_len - load_mode_len - delta
+                       : delta;
+               if (shift != 0) {
+                       ir_graph *const irg  = get_irn_irg(load);
+                       ir_node  *const cnst = new_r_Const_long(irg, mode_Iu, shift * 8);
                        store_value = new_r_Shr(get_nodes_block(load),
                                                                        store_value, cnst, store_mode);
                }
 
-               /* add an convert if needed */
-               if (store_mode != load_mode) {
-                       store_value = new_r_Conv(get_nodes_block(load), store_value, load_mode);
-               }
+               store_value = new_r_Conv(get_nodes_block(load), store_value, load_mode);
+       } else {
+               /* we would need some kind of bitcast node here */
+               return 0;
        }
 
        DBG_OPT_RAW(load, store_value);