+ /* arg, modes may be different */
+ m1 = get_tarval_mode(tv1);
+ m2 = get_tarval_mode(tv2);
+ if (m1 != m2) {
+ int size = get_mode_size_bits(m1) - get_mode_size_bits(m2);
+
+ if (size < 0) {
+ /* m1 is a small mode, cast up */
+ m1 = mode_is_signed(m1) ? find_signed_mode(m2) : find_unsigned_mode(m2);
+ if (m1 == NULL) {
+ /* should NOT happen, but if it does we give up here */
+ return may_alias;
+ }
+ tv1 = tarval_convert_to(tv1, m1);
+ } else if (size > 0) {
+ /* m2 is a small mode, cast up */
+ m2 = mode_is_signed(m2) ? find_signed_mode(m1) : find_unsigned_mode(m1);
+ if (m2 == NULL) {
+ /* should NOT happen, but if it does we give up here */
+ return may_alias;
+ }
+ tv2 = tarval_convert_to(tv2, m2);
+ }
+ /* here the size should be identical, check for signed */
+ if (get_mode_sign(m1) != get_mode_sign(m2)) {
+ /* find the signed */
+ if (mode_is_signed(m2)) {
+ tarval *t = tv1;
+ ir_mode *tm = m1;
+ tv1 = tv2; m1 = m2;
+ tv2 = t; m2 = tm;
+ }
+
+ /* m1 is now the signed one */
+ if (tarval_cmp(tv1, get_tarval_null(m1)) & (pn_Cmp_Eq|pn_Cmp_Gt)) {
+ /* tv1 is signed, but >= 0, simply cast into unsigned */
+ tv1 = tarval_convert_to(tv1, m2);
+ } else {
+ tv_size = new_tarval_from_long(size, m2);
+
+ if (tarval_cmp(tv2, tv_size) & (pn_Cmp_Eq|pn_Cmp_Gt)) {
+ /* tv1 is negative and tv2 >= tv_size, so the difference is bigger than size */
+ return no_alias;
+ }
+ /* tv_size > tv2, so we can subtract without overflow */
+ tv2 = tarval_sub(tv_size, tv2);
+
+ /* tv1 is < 0, so we can negate it */
+ tv1 = tarval_neg(tv1);
+
+ /* cast it into unsigned. for two-complement it does the right thing for MIN_INT */
+ tv1 = tarval_convert_to(tv1, m2);
+
+ /* now we can compare without overflow */
+ return tarval_cmp(tv1, tv2) & (pn_Cmp_Eq|pn_Cmp_Gt) ? no_alias : may_alias;
+ }
+ }
+ }