An OP_SEXT or a OP_ZEXT followed by a truncate to a size smaller than the original size is unneeded, the same result can be obtained by doing the truncate directly on the original value. Dualy, an OP_SEXT or a OP_ZEXT followed by a truncate to a size greater than the original size doesn't need the truncate, the same result can be obtained by doing the extend directly on the original value. Rearrange the inputs (src & orig_type) to bypass the unneeded operation. Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>