ICE: QImode(not SImode) operand should be passed to gen_vec_initv16qiqi in ashlv16qi3.

ICE: QImode(not SImode) operand should be passed to gen_vec_initv16qiqi in ashlv16qi3.

ix86_expand_vector_init expects vals to be a parallel containing
values of individual fields which should be either element mode of the
vector mode, or a vector mode with the same element mode and smaller
number of elements.

But in the expander ashlv16qi3, the second operand is SImode which
can't be directly passed to gen_vec_initv16qiqi.

gcc/ChangeLog:

	PR target/104451
	* config/i386/sse.md (<insn><mode>3): lowpart_subreg
	operands[2] from SImode to QImode.

gcc/testsuite/ChangeLog:

	PR target/104451
	* gcc.target/i386/pr104451.c: New test.