re PR target/71019 (AVX512BW instructions emitted even without AVX512BW)

re PR target/71019 (AVX512BW instructions emitted even without AVX512BW)

	PR target/71019
	* config/i386/sse.md (<sse2_avx2>_packssdw<mask_name>,
	<sse4_1_avx2>_packusdw<mask_name>): Make sure EVEX encoded insn
	is not emitted unless TARGET_AVX512BW.
	(<sse2_avx2>_packuswb<mask_name>, <sse2_avx2>_packsswb<mask_name>):
	Likewise.  For TARGET_AVX512BW, use "=v" constraint instead of "=x"
	for the result operand.

	* gcc.target/i386/avx512vl-pack-1.c: New test.
	* gcc.target/i386/avx512vl-pack-2.c: New test.
	* gcc.target/i386/avx512bw-pack-2.c: New test.

From-SVN: r236163