combos constant dataflow analysis has to be consistent with the localopt; this should...

[r27394]

diff --git a/ir/ir/iropt.c b/ir/ir/iropt.c
index 0c7cf97..be0d5db 100644 (file)
--- a/ir/ir/iropt.c
+++ b/ir/ir/iropt.c
@@ -487,8 +487,10 @@ static tarval *computed_value_Proj_Cmp(const ir_node *n)
        /*
         * BEWARE: a == a is NOT always True for floating Point values, as
         * NaN != NaN is defined, so we must check this here.
+        * (Note: Some pnc do still allow optimisations but we don't do them
+        *  here because we would get inconsistent with combos compute_Cmp then)
         */
-       if (left == right && (!mode_is_float(mode) || pn_cmp == pn_Cmp_Lt ||  pn_cmp == pn_Cmp_Gt)) {
+       if (left == right && !mode_is_float(mode)) {
                /* This is a trick with the bits used for encoding the Cmp
                   Proj numbers, the following statement is not the same:
                return new_tarval_from_long(pn_cmp == pn_Cmp_Eq, mode_b) */

diff --git a/ir/opt/combo.c b/ir/opt/combo.c
index f8a5070..3801c4f 100644 (file)
--- a/ir/opt/combo.c
+++ b/ir/opt/combo.c
@@ -2315,13 +2315,7 @@ static void compute_Cmp(node_t *node)
                        node->type.tv = tarval_b_true;
                }
        } else if (is_con(a) && is_con(b)) {
-               /* both nodes are constants, we can probably do something */
-               if (mode_is_float(mode)) {
-                       /* beware of NaN's */
-                       node->type.tv = tarval_bottom;
-               } else {
-                       node->type.tv = tarval_b_true;
-               }
+               node->type.tv = tarval_b_true;
        } else {
                node->type.tv = tarval_bottom;
        }
@@ -2347,13 +2341,16 @@ static void compute_Proj_Cmp(node_t *node, ir_node *cmp)
                node->type.tv = tarval_undefined;
        } else if (is_con(a) && is_con(b)) {
                default_compute(node);
-       } else if (r->part == l->part &&
-                  (!mode_is_float(get_irn_mode(l->node)) || pnc == pn_Cmp_Lt || pnc == pn_Cmp_Gt)) {
+
                /*
                 * BEWARE: a == a is NOT always True for floating Point values, as
                 * NaN != NaN is defined, so we must check this here.
+                * (while for some pnc we could still optimize we have to stay
+                *  consistent with compute_Cmp, so don't do anything for floats)
                 */
-               tv = pnc & pn_Cmp_Eq ? tarval_b_true: tarval_b_false;
+       } else if (r->part == l->part && !mode_is_float(get_irn_mode(l->node))) {
+
+               tv = pnc & pn_Cmp_Eq ? tarval_b_true : tarval_b_false;
 
                /* if the node was ONCE evaluated by all constants, but now
                   this breaks AND we get from the argument partitions a different