re PR tree-optimization/71643 (internal compiler error: in redirect_eh_edge_1, at tree-eh.c:2318 after r237427)

	PR tree-optimization/71643
	* tree-ssa-tail-merge.c (find_clusters_1): Ignore basic blocks with
	EH preds.

	* tree-ssa-tail-merge.c (deps_ok_for_redirect_from_bb_to_bb): Don't
	leak a bitmap if dep_bb is NULL.

	* g++.dg/opt/pr71643.C: New test.

From-SVN: r237783