* params.def (PARAM_MAX_VARTRACK_SIZE): New.

	* params.def (PARAM_MAX_VARTRACK_SIZE): New.
	* doc/invoke.texi: Document it.
	* var-tracking.c: Include toplev.h and params.h.
	(vt_find_locations): Return bool indicating success.  Compute
	hash sizes unconditionally.  Check new parameter, report.
	(variable_tracking_main_1): Check vt_find_locations results and
	retry.  Renamed from...
	(variable_tracking_main): ... this.  New wrapper to preserve
	flag_var_tracking_assignments.
	* Makefile.in (var-tracking.o): Adjust dependencies.

	* lib/prune.exp: Prune variable tracking size limit exceeded
	notes.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@156794 138bc75d-0d04-0410-961f-82ee72b054a4