test/signext.wast

(module
 (type $0 (func))
 (func $signext  (type $0)
  (local $0 i32)
  (local $1 i64)
  (drop (i32.extend8_s (get_local $0)))
  (drop (i32.extend16_s (get_local $0)))
  (drop (i64.extend8_s (get_local $1)))
  (drop (i64.extend16_s (get_local $1)))
  (drop (i64.extend32_s (get_local $1)))
 )
)