Function insert_shuffle

cranelift/fuzzgen/src/function_generator.rs:393–424

(
    fgen: &mut FunctionGenerator,
    builder: &mut FunctionBuilder,
    opcode: Opcode,
    _: &[Type],
    rets: &[Type],
)

}

fn insert_shuffle(
    fgen: &mut FunctionGenerator,
    builder: &mut FunctionBuilder,
    opcode: Opcode,
    _: &[Type],
    rets: &[Type],
) -> Result<()> {
    let ctrl_type = *rets.first().unwrap();

    let lhs = builder.use_var(fgen.get_variable_of_type(ctrl_type)?);
    let rhs = builder.use_var(fgen.get_variable_of_type(ctrl_type)?);

    let mask = {
        let mut lanes = [0u8; 16];
        for lane in lanes.iter_mut() {
            *lane = fgen.u.int_in_range(0..=31)?;
        }
        let lanes = ConstantData::from(lanes.as_ref());
        builder.func.dfg.immediates.push(lanes)
    };

    // This function is called for any `InstructionFormat::Shuffle`. Which today is just
    // `shuffle`, but lets assert that, just to be sure we don't accidentally insert
    // something else.
    assert_eq!(opcode, Opcode::Shuffle);
    let res = builder.ins().shuffle(lhs, rhs, mask);

    let target_var = fgen.get_variable_of_type(ctrl_type)?;
    builder.def_var(target_var, res);

    Ok(())
}

fn insert_ins_ext_lane(
    fgen: &mut FunctionGenerator,