Remark eval_shift_imm:
forall (P: expr -> Prop) n a0 a1 a2 a3,
(n = Int.zero -> P a0) ->
(0 <= Int.unsigned n < Int.zwordsize ->
Int.ltu n Int.iwordsize = true ->
Int.ltu (Int.sub Int.iwordsize n) Int.iwordsize = true ->
Int.ltu n Int64.iwordsize' = true ->
P a1) ->
(Int.zwordsize <= Int.unsigned n < Int64.zwordsize ->
Int.ltu (Int.sub n Int.iwordsize) Int.iwordsize = true ->
P a2) ->
P a3 ->
P (if Int.eq n Int.zero then a0
else if Int.ltu n Int.iwordsize then a1
else if Int.ltu n Int64.iwordsize' then a2
else a3).

Lemma eval_shrlimm:
forall n,
unary_constructor_sound (fun e => shrlimm e n) (fun v => Val.shrl v (Vint n)).