re PR target/47440 (Use LCM for vzeroupper insertion)

re PR target/47440 (Use LCM for vzeroupper insertion)

	PR target/47440
	* config/i386/i386.c (check_avx256_stores): Remove.
	(ix86_check_avx256_register): New.
	(ix86_avx_u128_mode_needed): Use ix86_check_avx256_register.
	Check the whole RTX for 256bit registers using for_each_rtx.
	(ix86_check_avx_stores): New.
	(ix86_avx_u128_mode_after): Change mode of CALL RTX to AVX_U128_CLEAN
	if there are no 256bit registers used in the function return register.
	(ix86_avx_u128_mode_entry): Use ix86_check_avx256_register.
	(ix86_avx_u128_mode_exit): Ditto.

From-SVN: r193409