Set callee_pass_avx256_p before emitting call instruction

Set callee_pass_avx256_p before emitting call instruction

gcc/

	PR target/56560
	* config/i386/i386.c (init_cumulative_args): Also set
	cum->callee_return_avx256_p.
	(ix86_function_arg): Set cum->callee_pass_avx256_p.  Set
	cfun->machine->callee_pass_avx256_p only when MODE == VOIDmode.

	* config/i386/i386.h (ix86_args): Add callee_pass_avx256_p and
	callee_return_avx256_p.

gcc/

	PR target/56560
	* gcc.target/i386/pr56560.c: New file.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/gcc-4_7-branch@196976 138bc75d-0d04-0410-961f-82ee72b054a4