- neither Abs nor Minus change the precision, so we can look-through them

  when checking for superflous strictConv

[r23460]

diff --git a/ir/ir/iropt.c b/ir/ir/iropt.c
index b4f5f0f..7e3c861 100644 (file)
--- a/ir/ir/iropt.c
+++ b/ir/ir/iropt.c
@@ -1214,19 +1214,39 @@ static ir_node *equivalent_node_Conv(ir_node *n) {
 restart:
        if (n_mode == a_mode) { /* No Conv necessary */
                if (get_Conv_strict(n)) {
-                       /* special case: the predecessor might be a also a Conv */
-                       if (is_Conv(a)) {
-                               if (! get_Conv_strict(a)) {
+                       ir_node *p = a;
+                       ir_node *s = n;
+
+                       /* neither Minus nor Abs nor Confirm change the precision,
+                          so we can "look-through" */
+                       for (;;) {
+                               if (is_Minus(p)) {
+                                       s = p;
+                                       p = get_Minus_op(p);
+                               } else if (is_Abs(p)) {
+                                       s = p;
+                                       p = get_Abs_op(p);
+                               } else if (is_Confirm(p)) {
+                                       s = p;
+                                       p = get_Confirm_value(p);
+                               } else {
+                                       /* stop here */
+                                       break;
+                               }
+                       }
+                       if (is_Conv(p)) {
+                               /* special case: the predecessor is also a Conv */
+                               if (! get_Conv_strict(p)) {
                                        /* first one is not strict, kick it */
-                                       a = get_Conv_op(a);
+                                       p = get_Conv_op(p);
                                        a_mode = get_irn_mode(a);
-                                       set_Conv_op(n, a);
+                                       set_irn_n(s, 1, p);
                                        goto restart;
                                }
                                /* else both are strict conv, second is superfluous */
                        } else {
-                               if (is_Proj(a)) {
-                                       ir_node *pred = get_Proj_pred(a);
+                               if (is_Proj(p)) {
+                                       ir_node *pred = get_Proj_pred(p);
                                        if (is_Load(pred)) {
                                                /* loads always return with the exact precision of n_mode */
                                                assert(get_Load_mode(pred) == n_mode);