re PR target/79671 (mapnik miscompilation on armv7hl since r235622)

re PR target/79671 (mapnik miscompilation on armv7hl since r235622)

2017-04-12  Richard Biener  <rguenther@suse.de>
	Bernd Edlinger  <bernd.edlinger@hotmail.de>

	PR middle-end/79671
	* alias.c (component_uses_parent_alias_set_from): Handle
	TYPE_TYPELESS_STORAGE.
	(get_alias_set): Likewise.
	* tree-core.h (tree_type_common): Add typeless_storage flag.
	* tree.h (TYPE_TYPELESS_STORAGE): New macro.
	* stor-layout.c (place_union_field): Set TYPE_TYPELESS_STORAGE
	for types containing members with TYPE_TYPELESS_STORAGE.
	(place_field): Likewise.
	(layout_type): Likewise for ARRAY_TYPE.
	* lto-streamer-out.c (hash_tree): Hash TYPE_TYPELESS_STORAGE.
	* tree-streamer-in.c (unpack_ts_type_common_value_fields): Stream
	TYPE_TYPELESS_STORAGE.
	* tree-streamer-out.c (pack_ts_type_common_value_fields): Likewise.

	lto/
	* lto.c (compare_tree_sccs_1): Compare TYPE_TYPELESS_STORAGE.

	cp/
	* tree.c (build_cplus_array_type): Set TYPE_TYPELESS_STORAGE
	for arrays of character or std::byte type.

	* g++.dg/torture/pr79671.C: New testcase.
	* g++.dg/lto/pr79671_0.C: Likewise.
	* g++.dg/lto/pr79671_1.c: Likewise.

Co-Authored-By: Bernd Edlinger <bernd.edlinger@hotmail.de>
From-SVN: r246866