handle indeces with different modes

[r15490]

diff --git a/ir/ana/irmemory.c b/ir/ana/irmemory.c
index a4bb3b3..596ba8e 100644 (file)
--- a/ir/ana/irmemory.c
+++ b/ir/ana/irmemory.c
@@ -118,10 +118,69 @@ static ir_alias_relation different_index(ir_node *idx1, ir_node *idx2, int size)
                tarval *tv1 = get_Const_tarval(idx1);
                tarval *tv2 = get_Const_tarval(idx2);
                tarval *tv, *tv_size;
+               ir_mode *m1, *m2;
 
                if (size == 0)
                        return tv1 == tv2 ? sure_alias : no_alias;
 
+               /* 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;
+                               }
+                       }
+               }
                if (tarval_cmp(tv1, tv2) == pn_Cmp_Gt) {
                        tarval *t = tv1;
                        tv1 = tv2;