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+(* *********************************************************************)
+(* *)
+(* The Compcert verified compiler *)
+(* *)
+(* Xavier Leroy, INRIA Paris-Rocquencourt *)
+(* *)
+(* 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. *)
+(* *)
+(* *********************************************************************)
+
+(** Recognition of combined operations, addressing modes and conditions
+ during the [CSE] phase. *)
+
+Require Import Coqlib.
+Require Import AST.
+Require Import Integers.
+Require Import Values.
+Require Import Memory.
+Require Import Op.
+Require Import Registers.
+Require Import RTL.
+Require Import CombineOp.
+Require Import CSE.
+
+Section COMBINE.
+
+Variable ge: genv.
+Variable sp: val.
+Variable m: mem.
+Variable get: valnum -> option rhs.
+Variable valu: valnum -> val.
+Hypothesis get_sound: forall v rhs, get v = Some rhs -> equation_holds valu ge sp m v rhs.
+
+Lemma combine_compimm_ne_0_sound:
+ forall x cond args,
+ combine_compimm_ne_0 get x = Some(cond, args) ->
+ eval_condition cond (map valu args) m = Val.cmp_bool Cne (valu x) (Vint Int.zero) /\
+ eval_condition cond (map valu args) m = Val.cmpu_bool (Mem.valid_pointer m) Cne (valu x) (Vint Int.zero).
+Proof.
+ intros until args. functional induction (combine_compimm_ne_0 get x); intros EQ; inv EQ.
+ (* of cmp *)
+ exploit get_sound; eauto. unfold equation_holds. simpl. intro EQ; inv EQ.
+ destruct (eval_condition cond (map valu args) m); simpl; auto. destruct b; auto.
+ (* of and *)
+ exploit get_sound; eauto. unfold equation_holds; simpl.
+ destruct args; try discriminate. destruct args; try discriminate. simpl.
+ intros EQ; inv EQ. destruct (valu v); simpl; auto.
+Qed.
+
+Lemma combine_compimm_eq_0_sound:
+ forall x cond args,
+ combine_compimm_eq_0 get x = Some(cond, args) ->
+ eval_condition cond (map valu args) m = Val.cmp_bool Ceq (valu x) (Vint Int.zero) /\
+ eval_condition cond (map valu args) m = Val.cmpu_bool (Mem.valid_pointer m) Ceq (valu x) (Vint Int.zero).
+Proof.
+ intros until args. functional induction (combine_compimm_eq_0 get x); intros EQ; inv EQ.
+ (* of cmp *)
+ exploit get_sound; eauto. unfold equation_holds. simpl. intro EQ; inv EQ.
+ rewrite eval_negate_condition.
+ destruct (eval_condition c (map valu args) m); simpl; auto. destruct b; auto.
+ (* of and *)
+ exploit get_sound; eauto. unfold equation_holds; simpl.
+ destruct args; try discriminate. destruct args; try discriminate. simpl.
+ intros EQ; inv EQ. destruct (valu v); simpl; auto.
+Qed.
+
+Theorem combine_cond_sound:
+ forall cond args cond' args',
+ combine_cond get cond args = Some(cond', args') ->
+ eval_condition cond' (map valu args') m = eval_condition cond (map valu args) m.
+Proof.
+ intros. functional inversion H; subst.
+ (* compimm ne zero *)
+ simpl; eapply combine_compimm_ne_0_sound; eauto.
+ (* compimm eq zero *)
+ simpl; eapply combine_compimm_eq_0_sound; eauto.
+ (* compuimm ne zero *)
+ simpl; eapply combine_compimm_ne_0_sound; eauto.
+ (* compuimm eq zero *)
+ simpl; eapply combine_compimm_eq_0_sound; eauto.
+Qed.
+
+Theorem combine_addr_sound:
+ forall addr args addr' args',
+ combine_addr get addr args = Some(addr', args') ->
+ eval_addressing ge sp addr' (map valu args') = eval_addressing ge sp addr (map valu args).
+Proof.
+ intros. functional inversion H; subst.
+ exploit get_sound; eauto. unfold equation_holds; simpl; intro EQ.
+ assert (forall vl,
+ eval_addressing ge sp (SelectOp.offset_addressing a n) vl =
+ option_map (fun v => Val.add v (Vint n)) (eval_addressing ge sp a vl)).
+ intros. destruct a; simpl; repeat (destruct vl; auto); simpl.
+ rewrite Val.add_assoc. auto.
+ repeat rewrite Val.add_assoc. auto.
+ rewrite Val.add_assoc. auto.
+ repeat rewrite Val.add_assoc. auto.
+ unfold symbol_address. destruct (Globalenvs.Genv.find_symbol ge i); auto.
+ unfold symbol_address. destruct (Globalenvs.Genv.find_symbol ge i); auto.
+ repeat rewrite <- (Val.add_commut v). rewrite Val.add_assoc. auto.
+ unfold symbol_address. destruct (Globalenvs.Genv.find_symbol ge i0); auto.
+ repeat rewrite <- (Val.add_commut (Val.mul v (Vint i))). rewrite Val.add_assoc. auto.
+ rewrite Val.add_assoc; auto.
+ rewrite H0. rewrite EQ. auto.
+Qed.
+
+Theorem combine_op_sound:
+ forall op args op' args',
+ combine_op get op args = Some(op', args') ->
+ eval_operation ge sp op' (map valu args') m = eval_operation ge sp op (map valu args) m.
+Proof.
+ intros. functional inversion H; subst.
+(* andimm *)
+ exploit get_sound; eauto. unfold equation_holds; simpl; intros. FuncInv.
+ rewrite <- H1. rewrite Val.and_assoc. auto.
+(* orimm *)
+ exploit get_sound; eauto. unfold equation_holds; simpl; intros. FuncInv.
+ rewrite <- H1. rewrite Val.or_assoc. auto.
+(* xorimm *)
+ exploit get_sound; eauto. unfold equation_holds; simpl; intros. FuncInv.
+ rewrite <- H1. rewrite Val.xor_assoc. auto.
+(* lea *)
+ simpl. eapply combine_addr_sound; eauto.
+(* cmp *)
+ simpl. decEq; decEq. eapply combine_cond_sound; eauto.
+Qed.
+
+End COMBINE.