Do not deconv reference modes.

[libfirm] / ir / opt / convopt.c

diff --git a/ir/opt/convopt.c b/ir/opt/convopt.c
index 3ee9687..e9fd907 100644 (file)
--- a/ir/opt/convopt.c
+++ b/ir/opt/convopt.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 1995-2007 University of Karlsruhe.  All right reserved.
+ * Copyright (C) 1995-2008 University of Karlsruhe.  All right reserved.
  *
  * This file is part of libFirm.
  *
@@ -106,10 +106,13 @@ int get_conv_costs(const ir_node *node, ir_mode *dest_mode)
                return conv_const_tv(node, dest_mode) == tarval_bad ? 1 : 0;
        }
 
+       if (is_Conv(node) &&
+                       is_downconv(get_irn_mode(node), dest_mode) &&
+                       get_irn_mode(get_Conv_op(node)) == dest_mode) {
+               return -1;
+       }
+
        if (get_irn_n_edges(node) > 1) {
-               if (is_Conv(node) && is_downconv(get_irn_mode(node), dest_mode)) {
-                       return get_conv_costs(get_Conv_op(node), dest_mode) - 1;
-               }
                DB((dbg, LEVEL_3, "multi outs at %+F\n", node));
                return 1;
        }
@@ -142,7 +145,8 @@ int get_conv_costs(const ir_node *node, ir_mode *dest_mode)
        }
 
        costs = 0;
-       arity = get_irn_arity(node);
+       // The shift count does not participate in the conv optimisation
+       arity = is_Shl(node) ? 1 : get_irn_arity(node);
        for (i = 0; i < arity; ++i) {
                ir_node *pred = get_irn_n(node, i);
                costs += imin(get_conv_costs(pred, dest_mode), 1);
@@ -177,10 +181,13 @@ ir_node *conv_transform(ir_node *node, ir_mode *dest_mode)
                }
        }
 
+       if (is_Conv(node) &&
+                       is_downconv(get_irn_mode(node), dest_mode) &&
+                       get_irn_mode(get_Conv_op(node)) == dest_mode) {
+               return get_Conv_op(node);
+       }
+
        if (get_irn_n_edges(node) > 1) {
-               if (is_Conv(node) && is_downconv(get_irn_mode(node), dest_mode)) {
-                       return conv_transform(get_Conv_op(node), dest_mode);
-               }
                return place_conv(node, dest_mode);
        }
 
@@ -192,7 +199,8 @@ ir_node *conv_transform(ir_node *node, ir_mode *dest_mode)
                return place_conv(node, dest_mode);
        }
 
-       arity = get_irn_arity(node);
+       // The shift count does not participate in the conv optimisation
+       arity = is_Shl(node) ? 1 : get_irn_arity(node);
        for (i = 0; i < arity; i++) {
                ir_node *pred = get_irn_n(node, i);
                ir_node *transformed;
@@ -247,6 +255,9 @@ void conv_opt_walker(ir_node *node, void *data)
        mode      = get_irn_mode(node);
        pred_mode = get_irn_mode(pred);
 
+       if (mode_is_reference(mode) || mode_is_reference(pred_mode))
+               return;
+
        if (!is_Phi(pred) && !is_downconv(pred_mode, mode))
                return;