PR tree-optimization/84478
	* gimple-fold.h (get_range_strlen): Add a bool argument defaulted to
	false.
	* gimple-fold.c (get_range_strlen): Make minlen const and assume it
	can't be NULL.  Change FUZZY from bool to int, for 1 add PHI/COND_EXPR
	support which is conservatively correct, for 2 only stay conservative
	for maxlen.  Formatting and comment capitalization fixes.  Add STRICT
	argument to the 2 argument get_range_strlen, adjust 6 arg
	get_range_strlen caller and clear minmaxlen[0] and [1] if it returned
	false.
	(get_maxval_strlen): Adjust 6 arg get_range_strlen caller.
	(gimple_fold_builtin_strlen): Pass true as last argument to
	get_range_strlen.

	* gcc.c-torture/execute/pr84478.c: New test.

Co-Authored-By: Martin Sebor <msebor@redhat.com>

From-SVN: r257870