There are many different kinds of loop unrolling, and RISC-V's V extension is not the only one. Itanium had the same issue: the loop unrolling assist in the ins

There are many different kinds of loop unrolling, and RISC-V's V extension is not the only one. Itanium had the same issue: the loop unrolling assist in the instruction set was not viewed by many compiler people as being sufficient.