Function float_limits

cranelift/fuzzgen/src/passes/fcvt.rs:39–64

Gets the max and min float values for this integer type Inserts fconst instructions with these values. When converting to integers, floats are truncated. This means that the maximum float value that can be converted into an i8 is 127.99999. And surprisingly the minimum float for an u8 is -0.99999! So get the limits of this type as a float value by adding or subtracting 1.0 from its min and max in

(
    pos: &mut FuncCursor,
    float_ty: Type,
    int_ty: Type,
    is_signed: bool,
)

// u8 is -0.99999! So get the limits of this type as a float value by adding or subtracting
// 1.0 from its min and max integer values.
fn float_limits(
    pos: &mut FuncCursor,
    float_ty: Type,
    int_ty: Type,
    is_signed: bool,
) -> (Value, Value) {
    let (min_int, max_int) = int_ty.bounds(is_signed);

    if float_ty == F32 {
        let (min, max) = if is_signed {
            ((min_int as i128) as f32, (max_int as i128) as f32)
        } else {
            (min_int as f32, max_int as f32)
        };

        (pos.ins().f32const(min - 1.0), pos.ins().f32const(max + 1.0))
    } else {
        let (min, max) = if is_signed {
            ((min_int as i128) as f64, (max_int as i128) as f64)
        } else {
            (min_int as f64, max_int as f64)
        };

        (pos.ins().f64const(min - 1.0), pos.ins().f64const(max + 1.0))
    }
}

/// Prepend instructions to inst to avoid traps
fn insert_fcvt_sequence(pos: &mut FuncCursor, inst: Inst) {