re PR tree-optimization/69162 (ICE in create_tmp_var, at gimple-expr.c:468)

	PR tree-optimization/69162
	* gimplify.c (gimplify_va_arg_expr): Encode original type of
	valist argument in another argument.
	(gimplify_modify_expr): Adjust for the above change.  Cleanup.
	* tree-stdarg.c (expand_ifn_va_arg_1): Use new 3rd argument
	to determine the va_list type, build a MEM_REF instead of
	build_fold_indirect_ref.

	* gcc.dg/pr69162.c: New test.

From-SVN: r232156