Transform a - (b - c) into (a - b) + c instead of a + (c - b) iff (b - c) is a pointer.

[r21056]

diff --git a/ir/ir/iropt.c b/ir/ir/iropt.c
index 22f08e4..85c5270 100644 (file)
--- a/ir/ir/iropt.c
+++ b/ir/ir/iropt.c
@@ -2363,18 +2363,30 @@ restart:
                n = new_rd_Add(dbg, irg, block, a, right, mode);
                DBG_OPT_ALGSIM0(oldn, n, FS_OPT_SUB_MINUS);
                return n;
-       } else if (is_Sub(b)) { /* a - (b - c) -> a + (c - b) */
+       } else if (is_Sub(b)) {
+               /* a - (b - c) -> a + (c - b)
+                *             -> (a - b) + c iff (b - c) is a pointer */
                ir_graph *irg     = current_ir_graph;
                dbg_info *s_dbg   = get_irn_dbg_info(b);
                ir_node  *s_block = get_nodes_block(b);
-               ir_node  *s_left  = get_Sub_right(b);
-               ir_node  *s_right = get_Sub_left(b);
+               ir_node  *s_left  = get_Sub_left(b);
+               ir_node  *s_right = get_Sub_right(b);
                ir_mode  *s_mode  = get_irn_mode(b);
-               ir_node  *sub     = new_rd_Sub(s_dbg, irg, s_block, s_left, s_right, s_mode);
-               dbg_info *a_dbg   = get_irn_dbg_info(n);
-               ir_node  *a_block = get_nodes_block(n);
+               if (s_mode == mode_P) {
+                       ir_node  *sub     = new_rd_Sub(s_dbg, irg, s_block, a, s_left, mode);
+                       dbg_info *a_dbg   = get_irn_dbg_info(n);
+                       ir_node  *a_block = get_nodes_block(n);
+
+                       if (s_mode != mode)
+                               s_right = new_r_Conv(irg, a_block, s_right, mode);
+                       n = new_rd_Add(a_dbg, irg, a_block, sub, s_right, mode);
+               } else {
+                       ir_node  *sub     = new_rd_Sub(s_dbg, irg, s_block, s_right, s_left, s_mode);
+                       dbg_info *a_dbg   = get_irn_dbg_info(n);
+                       ir_node  *a_block = get_nodes_block(n);
 
-               n = new_rd_Add(a_dbg, irg, a_block, a, sub, mode);
+                       n = new_rd_Add(a_dbg, irg, a_block, a, sub, mode);
+               }
                DBG_OPT_ALGSIM0(oldn, n, FS_OPT_SUB_TO_ADD);
                return n;
        } else if (is_Mul(b)) { /* a - (b * C) -> a + (b * -C) */