Local Open Scope logic.

Lemma semax_while_peel:
forall {CS: compspecs} {Espec: OracleKind} Inv Delta P expr body R,
@semax CS Espec Delta P (Ssequence (Sifthenelse expr Sskip Sbreak) body)
(loop1_ret_assert Inv R) ->
@semax CS Espec Delta Inv (Swhile expr body) R ->
@semax CS Espec Delta P (Swhile expr body) R.