PR tree-optimization/56490
	* params.def (PARAM_UNINIT_CONTROL_DEP_ATTEMPTS): New param.
	* tree-ssa-uninit.c: Include params.h.
	(compute_control_dep_chain): Add num_calls argument, return false
	if it exceed PARAM_UNINIT_CONTROL_DEP_ATTEMPTS param, pass
	num_calls to recursive call.
	(find_predicates): Change dep_chain into normal array,
	cur_chain into auto_vec<edge, MAX_CHAIN_LEN + 1>, add num_calls
	variable and adjust compute_control_dep_chain caller.
	(find_def_preds): Likewise.

From-SVN: r207988