[Question] Combining two vector registers with different LMUL

[Tameem97]

[Question] Combining two vector registers with different LMUL

[dzaima]

vuint8mf2_t ext1 = __riscv_vlmul_ext_v_u8mf4_u8mf2(v1);
vuint8mf2_t ext2 = __riscv_vlmul_ext_v_u8mf4_u8mf2(v2);
size_t vl = __riscv_vsetvlmax_e8mf2();
vuint8mf2_t res = __riscv_vslideup_vx_u8mf2(ext1, ext2, vl/2, vl);

Though, if you were to use LMUL ≥ 1, e.g. with inputs of vuint8m1_t v1, v2 you could

vuint8m2_t ext1 = __riscv_vlmul_ext_v_u8m1_u8m2(v1);
vuint8m2_t res = __riscv_vset_v_u8m1_u8m2(ext1, 1, v2);

But I would guess that there probably is some alternative way to achieve what you want (especially considering that such vector concatenation is quite a weird operation due to varying VLEN across RISC-V V implementations).

[Tameem97]

Thanks @dzaima for answer.
Yes, there are some other ways also but they are taking more intrinsics then I anticipated so this is the only thing which I got stuck with for LMUL<1