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(*              The Compcert verified compiler                         *)
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(*                  Xavier Leroy, INRIA Paris                          *)
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(*  Copyright Institut National de Recherche en Informatique et en     *)
(*  Automatique.  All rights reserved.  This file is distributed       *)
(*  under the terms of the INRIA Non-Commercial License Agreement.     *)
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(** Correctness proof for x86-64 generation: auxiliary results. *)
Local Open Scope error_monad_scope.
(** * Correspondence between Mach registers and x86 registers *)
(** Useful properties of the PC register. *)

Lemma nextinstr_nf_inv:
forall r rs,
match r with PC => False | CR _ => False | _ => True end ->
(nextinstr_nf rs)#r = rs#r.