Function transmute_scalar 

pub(super) fn transmute_scalar<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
    bx: &mut Bx,
    imm: Bx::Value,
    from_scalar: Scalar,
    to_scalar: Scalar,
) -> Bx::Value

Transmutes a single scalar value imm from from_scalar to to_scalar.

This is expected to be in immediate form, as seen in OperandValue::Immediate or OperandValue::Pair (so i1 for bools, not i8, for example).

ICEs if the passed-in imm is not a value of the expected type for from_scalar, such as if it’s a vector or a pair.