/*
- * 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.
*
* @author Michael Beck
* @version $Id$
*/
-#ifdef HAVE_CONFIG_H
-# include "config.h"
-#endif
+#include "config.h"
#undef DEBUG_CONFIRM
* This is a often needed case, so we handle here Confirm
* nodes too.
*/
-int value_not_zero(ir_node *n, ir_node **confirm) {
+int value_not_zero(const ir_node *n, ir_node_cnst_ptr *confirm) {
#define RET_ON(x) if (x) { *confirm = n; return 1; }; break
tarval *tv;
*confirm = NULL;
/* there might be several Confirms one after other that form an interval */
- for (; is_Confirm(n); n = get_Confirm_value(n)) {
+ for (;;) {
+ if (is_Minus(n) || is_Abs(n)) {
+ /* we can safely skip Minus and Abs when checking for != 0 */
+ n = get_unop_op(n);
+ continue;
+ }
+ if (! is_Confirm(n))
+ break;
+
/*
* Note: A Confirm is never after a Const. So,
* we simply can check the bound for being a Const
default:
break;
}
+ n = get_Confirm_value(n);
}
tv = value_of(n);
* - A SymConst(entity) is NEVER a NULL pointer
* - Confirms are evaluated
*/
-int value_not_null(ir_node *n, ir_node **confirm) {
- ir_op *op;
+int value_not_null(const ir_node *n, ir_node_cnst_ptr *confirm) {
+ tarval *tv;
*confirm = NULL;
- n = skip_Cast(n);
+ n = skip_Cast_const(n);
+
+ tv = value_of(n);
+ if (tarval_is_constant(tv) && ! tarval_is_null(tv))
+ return 1;
- op = get_irn_op(n);
assert(mode_is_reference(get_irn_mode(n)));
if (get_opt_sel_based_null_check_elim()) {
/* skip all Sel nodes and Cast's */
- while (op == op_Sel) {
+ while (is_Sel(n)) {
n = skip_Cast(get_Sel_ptr(n));
- 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;
+ } else if (n == get_irg_frame(current_ir_graph)) {
+ /* local references are never NULL */
return 1;
- if (op == op_Const) {
- tarval *tv = get_Const_tarval(n);
-
- if (tv != tarval_bad && classify_tarval(tv) != TV_CLASSIFY_NULL)
- return 1;
} else {
+ /* check for more Confirms */
for (; is_Confirm(n); n = skip_Cast(get_Confirm_value(n))) {
- if (get_Confirm_cmp(n) == pn_Cmp_Lg &&
- classify_Const(get_Confirm_bound(n)) == CNST_NULL) {
+ if (get_Confirm_cmp(n) == pn_Cmp_Lg) {
+ ir_node *bound = get_Confirm_bound(n);
+ tarval *tv = value_of(bound);
+
+ if (tarval_is_null(tv)) {
*confirm = n;
return 1;
+ }
}
}
}
tarval *tv, *c;
ir_mode *mode;
pn_Cmp cmp, ncmp;
+ int negate = 1;
+
+ for (;;) {
+ ir_opcode code = get_irn_opcode(n);
- if (get_irn_op(n) != op_Confirm)
+ switch (code) {
+ case iro_Minus:
+ negate *= -1;
+ n = get_Minus_op(n);
+ continue;
+ case iro_Confirm:
+ break;
+ default:
+ return value_classified_unknown;
+ }
+ break;
+ }
+ if (!is_Confirm(n))
return value_classified_unknown;
tv = value_of(get_Confirm_bound(n));
return value_classified_unknown;
/* yep, negative */
- return value_classified_negative;
+ return value_classified_negative * negate;
case pn_Cmp_Ge:
/*
}
/* yep, positive */
- return value_classified_positive;
+ return value_classified_positive * negate;
default:
return value_classified_unknown;
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 */
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);
+ const 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)