===================================================================
@@ -3081,9 +3081,12 @@ vect_prune_runtime_alias_test_list (loop
|| !tree_fits_shwi_p (dr_a2->offset))
continue;
+ /* Make sure dr_a1 starts left of dr_a2. */
+ if (tree_int_cst_lt (dr_a2->offset, dr_a1->offset))
+ std::swap (*dr_a1, *dr_a2);
+
unsigned HOST_WIDE_INT diff
- = absu_hwi (tree_to_shwi (dr_a2->offset)
- - tree_to_shwi (dr_a1->offset));
+ = tree_to_shwi (dr_a2->offset) - tree_to_shwi (dr_a1->offset);
/* Now we check if the following condition is satisfied: