re PR tree-optimization/87609 (miscompilation with restrict and loop)

re PR tree-optimization/87609 (miscompilation with restrict and loop)

2019-02-22  Richard Biener  <rguenther@suse.de>

	PR middle-end/87609
	* cfghooks.h (dependence_hash): New typedef.
	(struct copy_bb_data): New type.
	(cfg_hooks::duplicate_block): Adjust to take a copy_bb_data argument.
	(duplicate_block): Likewise.
	* cfghooks.c (duplicate_block): Pass down copy_bb_data.
	(copy_bbs): Create and pass down copy_bb_data.
	* cfgrtl.c (cfg_layout_duplicate_bb): Adjust.
	(rtl_duplicate_bb): Likewise.
	* tree-cfg.c (gimple_duplicate_bb): If the copy_bb_data arg is not NULL
	remap dependence info.

	* gcc.dg/torture/restrict-7.c: New testcase.

From-SVN: r269098