PR tree-optimization/44485
	* calls.c (flags_from_decl_or_type): For const or pure
	noreturn functions return ECF_LOOPING_CONST_OR_PURE|ECF_NORETURN
	together with ECF_CONST resp. ECF_PURE.
	* builtins.c (expand_builtin): Use flags_from_decl_or_type
	instead of querying flags directly.
	* tree-ssa-loop-niter.c (finite_loop_p): Likewise.
	* tree-ssa-dce.c (find_obviously_necessary_stmts): Likewise.

	* gcc.dg/pr44485.c: New test.

From-SVN: r163568