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).

Theorem eval_shrxlimm:
forall le a n x z,
Archi.ptr64 = false ->
eval_expr ge sp e m le a x ->
Val.shrxl x (Vint n) = Some z ->
exists v, eval_expr ge sp e m le (shrxlimm a n) v /\ Val.lessdef z v.