re PR middle-end/54838 (ICE: in merge_latch_edges, at cfgloop.c:678 with -ftracer)

re PR middle-end/54838 (ICE: in merge_latch_edges, at cfgloop.c:678 with -ftracer)

2012-12-18  Richard Biener  <rguenther@suse.de>

	PR middle-end/54838
	* cfgloopmanip.c (fix_loop_structure): Re-discover latch
	edges first and mark loops for removal if no latch edges remain.
	Properly re-create LOOPS_HAVE_FALLTHRU_PREHEADERS.
	* loop-init.c (loop_optimizer_finalize): Set
	LOOPS_MAY_HAVE_MULTIPLE_LATCHES.

	* g++.dg/torture/pr54838.C: New testcase.

From-SVN: r194582