PR middle-end/50865
	PR tree-optimization/69097
	* fold-const.h (expr_not_equal_to): New prototype.
	* fold-const.c: Include stringpool.h and tree-ssanames.h.
	(expr_not_equal_to): New function.
	* match.pd (X % -Y is the same as X % Y): Don't optimize
	unless X is known not to be equal to minimum or Y is known
	not to be equal to -1.
	* tree-vrp.c (simplify_div_or_mod_using_ranges): Add GSI argument.
	fold TRUNC_MOD_EXPR if the second argument is not a power of two.
	(simplify_stmt_using_ranges): Adjust caller.
	(vrp_finalize): Call set_value_range on SSA_NAMEs before calling
	substitute_and_fold.

	* gcc.c-torture/execute/pr50865.c: New test.
	* gcc.c-torture/execute/pr69097-1.c: New test.
	* gcc.c-torture/execute/pr69097-2.c: New test.
	* gcc.dg/pr69097-1.c: New test.
	* gcc.dg/pr69097-2.c: New test.

From-SVN: r232188