re PR tree-optimization/25737 (ACATS c974001 c974013 hang with struct aliasing)

re PR tree-optimization/25737 (ACATS c974001 c974013 hang with struct aliasing)

	PR tree-optimization/25737
	* tree.h (struct tree_struct_field_tag): Add new field alias_set.
	(SFT_NONADDRESSABLE_P, SFT_ALIAS_SET): New macros.
	* tree-flow.h (struct fieldoff): Add new field alias_set.
	* tree-ssa-structalias.c (push_fields_onto_fieldstack): Add new
	argument addressable_type.  Set alias_set of fieldoff.
	* tree-ssa-alias.c (create_sft): Add new argument alias_set.
	(create_overlap_variables_for): Pass alias_set from fieldoff to
	create_sft.
	* alias.c (get_alias_set): Use alias_set from SFT if set.

From-SVN: r125890