attempt to fix broken type based alias analysis

[r22133]

diff --git a/ir/ana/irmemory.c b/ir/ana/irmemory.c
index 720e6de..7d279a0 100644 (file)
--- a/ir/ana/irmemory.c
+++ b/ir/ana/irmemory.c
@@ -354,6 +354,7 @@ static ir_alias_relation different_types(ir_node *adr1, ir_node *adr2)
                ir_type *tp2 = get_entity_type(ent2);
 
                if (tp1 != tp2) {
+#if 0
                        if (is_Pointer_type(tp1) && is_Pointer_type(tp2)) {
                                /* do deref until no pointer types are found */
                                do {
@@ -361,6 +362,7 @@ static ir_alias_relation different_types(ir_node *adr1, ir_node *adr2)
                                        tp2 = get_pointer_points_to_type(tp2);
                                } while (is_Pointer_type(tp1) && is_Pointer_type(tp2));
                        }
+#endif
 
                        if (get_type_tpop(tp1) != get_type_tpop(tp2)) {
                                /* different type structure */
@@ -561,6 +563,32 @@ static ir_alias_relation _get_alias_relation(
                        return different_sel_offsets(adr1, adr2);
        }
 
+       /* Type based alias analysis */
+       if (options & aa_opt_type_based) {
+               ir_alias_relation rel;
+
+               if (options & aa_opt_byte_type_may_alias) {
+                       if (get_mode_size_bits(mode1) == 8 || get_mode_size_bits(mode2) == 8) {
+                               /* One of the modes address a byte. Assume a ir_may_alias and leave
+                                  the type based check. */
+                               goto leave_type_based_alias;
+                       }
+               }
+               /* cheap check: If the mode sizes did not match, the types MUST be different */
+               if (get_mode_size_bits(mode1) != get_mode_size_bits(mode2))
+                       return ir_no_alias;
+
+               /* cheap test: if only one is a reference mode, no alias */
+               if (mode_is_reference(mode1) != mode_is_reference(mode2))
+                       return ir_no_alias;
+
+               /* try rule R5 */
+               rel = different_types(orig_adr1, orig_adr2);
+               if (rel != ir_may_alias)
+                       return rel;
+leave_type_based_alias:;
+       }
+
        class1 = classify_pointer(irg, base1, ent1);
        class2 = classify_pointer(irg, base2, ent2);
 
@@ -592,32 +620,6 @@ static ir_alias_relation _get_alias_relation(
                return ir_may_alias;
        }
 
-       /* Type based alias analysis */
-       if (options & aa_opt_type_based) {
-               ir_alias_relation rel;
-
-               if (options & aa_opt_byte_type_may_alias) {
-                       if (get_mode_size_bits(mode1) == 8 || get_mode_size_bits(mode2) == 8) {
-                               /* One of the modes address a byte. Assume a ir_may_alias and leave
-                                  the type based check. */
-                               goto leave_type_based_alias;
-                       }
-               }
-               /* cheap check: If the mode sizes did not match, the types MUST be different */
-               if (get_mode_size_bits(mode1) != get_mode_size_bits(mode2))
-                       return ir_no_alias;
-
-               /* cheap test: if only one is a reference mode, no alias */
-               if (mode_is_reference(mode1) != mode_is_reference(mode2))
-                       return ir_no_alias;
-
-               /* try rule R5 */
-               rel = different_types(orig_adr1, orig_adr2);
-               if (rel != ir_may_alias)
-                       return rel;
-leave_type_based_alias:;
-       }
-
        /* do we have a language specific memory disambiguator? */
        if (language_disambuigator) {
                ir_alias_relation rel = (*language_disambuigator)(irg, orig_adr1, mode1, orig_adr2, mode2);