PR target/18916
	* builtins.c (std_gimplify_va_arg_expr): Adjust alignment of *ap.
	* expr.h (struct locate_and_pad_arg_data): Add "boundary".
	* function.c (locate_and_pad_parm): Set new field.
	(assign_parm_find_stack_rtl): Use it instead of FUNCTION_ARG_BOUNDARY.
	Tweak where_pad test to include "none".  Always set mem align for
	stack_parm.
	(assign_parm_adjust_stack_rtl): Discard stack_parm if alignment
	not sufficient for type.
	(assign_parm_setup_block): If stack_parm is zero on entry, always
	make a new stack local.  Block move old stack parm if necessary
	to new aligned stack local.
	(assign_parm_setup_stack): Use a block move to handle
	potentially misaligned entry_parm.
	(assign_parms_unsplit_complex): Specify required alignment when
	creating stack local.
	* calls.c (compute_argument_addresses): Override alignment of stack
	arg calculated from its type with the alignment given by
	FUNCTION_ARG_BOUNDARY.
	(store_one_arg): Likewise.

From-SVN: r93179