re PR c++/71694 (store-data race with bitfields and tail-padding in C++)

re PR c++/71694 (store-data race with bitfields and tail-padding in C++)

2016-12-16  Richard Biener  <rguenther@suse.de>

	PR c++/71694
	* langhooks-def.h (lhd_unit_size_without_reusable_padding): Declare.
	(LANG_HOOKS_UNIT_SIZE_WITHOUT_REUSABLE_PADDING): Define.
	(LANG_HOOKS_FOR_TYPES_INITIALIZER): Adjust.
	* langhooks.h (struct lang_hooks_for_types): Add
	unit_size_without_reusable_padding.
	* langhooks.c (lhd_unit_size_without_reusable_padding): New.
	* stor-layout.c (finish_bitfield_representative): Use
	unit_size_without_reusable_padding langhook to decide on the
	last representatives size.

	cp/
	* cp-objcp-common.h (cp_unit_size_without_reusable_padding): Declare.
	(LANG_HOOKS_UNIT_SIZE_WITHOUT_REUSABLE_PADDING): Define.
	* cp-objcp-common.c (cp_unit_size_without_reusable_padding): New.

	* g++.dg/pr71694.C: New testcase.

From-SVN: r243738