updated

[libfirm] / ir / ir / irarch.c

diff --git a/ir/ir/irarch.c b/ir/ir/irarch.c
index 17c8f41..ada45d6 100644 (file)
--- a/ir/ir/irarch.c
+++ b/ir/ir/irarch.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.
  *
@@ -229,8 +229,8 @@ static unsigned char *value_to_condensed(mul_env *env, tarval *tv, int *pr) {
  * Calculate the gain when using the generalized complementary technique
  */
 static int calculate_gain(unsigned char *R, int r) {
-       int max_gain = -1;
-       int idx, i;
+       int max_gain = 0;
+       int idx = -1, i;
        int gain;
 
        /* the gain for r == 1 */
@@ -244,9 +244,7 @@ static int calculate_gain(unsigned char *R, int r) {
                        idx = i;
                }
        }
-       if (max_gain > 0)
-               return idx;
-       return -1;
+       return idx;
 }
 
 /**
@@ -932,15 +930,20 @@ ir_node *arch_dep_replace_div_by_const(ir_node *irn) {
                                ir_node *k_node;
                                ir_node *curr = left;
 
-                               if (k != 1) {
-                                       k_node = new_r_Const_long(current_ir_graph, block, mode_Iu, k - 1);
-                                       curr   = new_rd_Shrs(dbg, current_ir_graph, block, left, k_node, mode);
-                               }
+                               /* create the correction code for signed values only if there might be a remainder */
+                               if (! is_Div_remainderless(irn)) {
+                                       if (k != 1) {
+                                               k_node = new_r_Const_long(current_ir_graph, block, mode_Iu, k - 1);
+                                               curr   = new_rd_Shrs(dbg, current_ir_graph, block, left, k_node, mode);
+                                       }
 
-                               k_node = new_r_Const_long(current_ir_graph, block, mode_Iu, bits - k);
-                               curr   = new_rd_Shr(dbg, current_ir_graph, block, curr, k_node, mode);
+                                       k_node = new_r_Const_long(current_ir_graph, block, mode_Iu, bits - k);
+                                       curr   = new_rd_Shr(dbg, current_ir_graph, block, curr, k_node, mode);
 
-                               curr   = new_rd_Add(dbg, current_ir_graph, block, left, curr, mode);
+                                       curr   = new_rd_Add(dbg, current_ir_graph, block, left, curr, mode);
+                               } else {
+                                       k_node = left;
+                               }
 
                                k_node = new_r_Const_long(current_ir_graph, block, mode_Iu, k);
                                res    = new_rd_Shrs(dbg, current_ir_graph, block, curr, k_node, mode);