On the other hand the instruction set extensions can be bulky. For instance the bit manipulation set at https://github.com/riscv/riscv-bitmanip https://github.

On the other hand the instruction set extensions can be bulky. For instance the bit manipulation set at https://github.com/riscv/riscv-bitmanip https://github.com/riscv/riscv-bitmanip adds frequently used operations like conditional move and population count, but also adds things like "multiply binary matrix" and "generalized or-combine", which I'm not sure even exists in X86 or AMD64.