make verifier a bit less strict about keeps

[libfirm] / ir / opt / opt_confirms.c

diff --git a/ir/opt/opt_confirms.c b/ir/opt/opt_confirms.c
index 0e6ca9a..28e0ef7 100644 (file)
--- a/ir/opt/opt_confirms.c
+++ b/ir/opt/opt_confirms.c
@@ -190,12 +190,17 @@ int value_not_null(ir_node *n, ir_node **confirm) {
                        op = get_irn_op(n);
                }
        }
-       if (op == op_SymConst && get_SymConst_kind(n) == symconst_addr_ent)
+       if (is_Global(n)) {
+               /* global references are never NULL */
                return 1;
-       if (op == op_Const) {
-               if (!is_Const_null(n))
-                       return 1;
+       } else if (n == get_irg_frame(current_ir_graph)) {
+               /* local references are never NULL */
+               return 1;
+       } else if (op == op_Const) {
+               /* explicit non-NULL addresses */
+               return !is_Const_null(n);
        } else {
+               /* check for more Confirms */
                for (; is_Confirm(n); n = skip_Cast(get_Confirm_value(n))) {
                        if (get_Confirm_cmp(n) != pn_Cmp_Lg) {
                                ir_node *bound = get_Confirm_bound(n);
@@ -622,8 +627,9 @@ tarval *computed_value_Cmp_Confirm(ir_node *cmp, ir_node *left, ir_node *right,
 
                pnc = get_inversed_pnc(pnc);
        } else if (! is_Confirm(left)) {
-               /* no Confirm on either one side, finish */
-               return tarval_bad;
+               /* nothing more found */
+               tv = tarval_bad;
+               goto check_null_case;
        }
 
        /* ok, here at least left is a Confirm, right might be */
@@ -756,6 +762,24 @@ tarval *computed_value_Cmp_Confirm(ir_node *cmp, ir_node *left, ir_node *right,
                        get_interval(&l_iv, l_bound, l_pnc),
                        get_interval_from_tv(&r_iv, tv),
                        pnc);
+       } else {
+check_null_case:
+               /* check some other cases */
+               if ((pnc == pn_Cmp_Eq || pnc == pn_Cmp_Lg) &&
+                       is_Const(right) && is_Const_null(right)) {
+                       /* for == 0 or != 0 we have some special tools */
+                       ir_mode *mode = get_irn_mode(left);
+                       ir_node *dummy;
+                       if (mode_is_reference(mode)) {
+                               if (value_not_null(left, &dummy)) {
+                                       tv = pnc == pn_Cmp_Eq ? tarval_b_false : tarval_b_true;
+                               }
+                       } else {
+                               if (value_not_zero(left, &dummy)) {
+                                       tv = pnc == pn_Cmp_Eq ? tarval_b_false : tarval_b_true;
+                               }
+                       }
+               }
        }
 
        if (tv != tarval_bad)