New modref/ipa_modref optimization passes

[Jan Hubicka]

Hi,
this is patch I am using to fix the assumed_alias_type.f90 failure by
simply arranging alias set 0 for the problematic array descriptor.

I am not sure this is the best option, but I suppose it is better than
setting all array descritors to have same canonical type (as done by
LTO)?

Honza

	* trans-types.c (gfc_get_array_type_bounds): Set alias set to 0 for
	arrays of unknown element type.
diff --git a/gcc/fortran/trans-types.c b/gcc/fortran/trans-types.c
index 26fdb2803a7..bef3d270c06 100644
--- a/gcc/fortran/trans-types.c
+++ b/gcc/fortran/trans-types.c
@@ -1903,6 +1903,12 @@ gfc_get_array_type_bounds (tree etype, int dimen, int codimen, tree * lbound,
   base_type = gfc_get_array_descriptor_base (dimen, codimen, false);
   TYPE_CANONICAL (fat_type) = base_type;
   TYPE_STUB_DECL (fat_type) = TYPE_STUB_DECL (base_type);
+  /* Arrays of unknown type must alias with all array descriptors.  */
+  if (etype == ptr_type_node)
+    {
+      TYPE_ALIAS_SET (base_type) = 0;
+      TYPE_ALIAS_SET (fat_type) = 0;
+    }
 
   tmp = TYPE_NAME (etype);
   if (tmp && TREE_CODE (tmp) == TYPE_DECL)