re PR tree-optimization/68031 (cc1 crashes when compiling newlib / mktm_r.c)

2015-10-21  Richard Biener  <rguenther@suse.de>

	PR middle-end/68031
	* fold-const.c: Include tree-ssa-operands.h and tree-into-ssa.h.
	(tree_ssa_name_nonnegative_warnv_p): Fold into ...
	(tree_single_nonnegative_warnv_p): ... here.  For SSA names
	make sure they are not registered for update.

	* gcc.dg/torture/pr68031.c: New testcase.

From-SVN: r229118