From 336a1f906a9c617e68e9d43e244bf42e9bdbae64 Mon Sep 17 00:00:00 2001
From: xleroy <xleroy@fca1b0fc-160b-0410-b1d3-a4f43f01ea2e>
Date: Wed, 9 Apr 2014 13:26:16 +0000
Subject: Constprop: use "not" for "xorimm(-1)"; optimize == 1 and != 0
 comparisons over booleans. Select*: more systematic constant propagation;
 don't CP shifts by amounts outside of [0..31]. Driver: timer for whole
 compilation.

git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@2452 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e
---
 arm/ConstpropOpproof.v | 50 +++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 47 insertions(+), 3 deletions(-)

(limited to 'arm/ConstpropOpproof.v')

diff --git a/arm/ConstpropOpproof.v b/arm/ConstpropOpproof.v
index 90e18f20..7cf5879a 100644
--- a/arm/ConstpropOpproof.v
+++ b/arm/ConstpropOpproof.v
@@ -126,6 +126,52 @@ Proof.
 - auto.
 Qed.
 
+Lemma make_cmp_base_correct:
+  forall c args vl,
+  vl = map (fun r => AE.get r ae) args ->
+  let (op', args') := make_cmp_base c args vl in
+  exists v, eval_operation ge (Vptr sp Int.zero) op' rs##args' m = Some v 
+         /\ Val.lessdef (Val.of_optbool (eval_condition c rs##args m)) v.
+Proof.
+  intros. unfold make_cmp_base. 
+  generalize (cond_strength_reduction_correct c args vl H). 
+  destruct (cond_strength_reduction c args vl) as [c' args']. intros EQ.
+  econstructor; split. simpl; eauto. rewrite EQ. auto. 
+Qed.
+
+Lemma make_cmp_correct:
+  forall c args vl,
+  vl = map (fun r => AE.get r ae) args ->
+  let (op', args') := make_cmp c args vl in
+  exists v, eval_operation ge (Vptr sp Int.zero) op' rs##args' m = Some v 
+         /\ Val.lessdef (Val.of_optbool (eval_condition c rs##args m)) v.
+Proof.
+  intros c args vl.
+  assert (Y: forall r, vincl (AE.get r ae) (Uns 1) = true ->
+             rs#r = Vundef \/ rs#r = Vint Int.zero \/ rs#r = Vint Int.one).
+  { intros. apply vmatch_Uns_1 with bc. eapply vmatch_ge. eapply vincl_ge; eauto. apply MATCH. }
+  unfold make_cmp. case (make_cmp_match c args vl); intros.
+- destruct (Int.eq_dec n Int.one && vincl v1 (Uns 1)) eqn:E1.
+  simpl in H; inv H. InvBooleans. subst n. 
+  exists (rs#r1); split; auto. simpl.
+  exploit Y; eauto. intros [A | [A | A]]; rewrite A; simpl; auto.
+  destruct (Int.eq_dec n Int.zero && vincl v1 (Uns 1)) eqn:E0.
+  simpl in H; inv H. InvBooleans. subst n. 
+  exists (Val.xor rs#r1 (Vint Int.one)); split; auto. simpl.
+  exploit Y; eauto. intros [A | [A | A]]; rewrite A; simpl; auto.
+  apply make_cmp_base_correct; auto.
+- destruct (Int.eq_dec n Int.zero && vincl v1 (Uns 1)) eqn:E0.
+  simpl in H; inv H. InvBooleans. subst n. 
+  exists (rs#r1); split; auto. simpl.
+  exploit Y; eauto. intros [A | [A | A]]; rewrite A; simpl; auto.
+  destruct (Int.eq_dec n Int.one && vincl v1 (Uns 1)) eqn:E1.
+  simpl in H; inv H. InvBooleans. subst n. 
+  exists (Val.xor rs#r1 (Vint Int.one)); split; auto. simpl.
+  exploit Y; eauto. intros [A | [A | A]]; rewrite A; simpl; auto.
+  apply make_cmp_base_correct; auto.
+- apply make_cmp_base_correct; auto.
+Qed.
+
 Lemma make_addimm_correct:
   forall n r,
   let (op, args) := make_addimm n r in
@@ -416,9 +462,7 @@ Proof.
 (* singleoffloat *)
   InvApproxRegs; SimplVM; inv H0. apply make_singleoffloat_correct; auto.
 (* cmp *)
-  generalize (cond_strength_reduction_correct c args0 vl0). 
-  destruct (cond_strength_reduction c args0 vl0) as [c' args']; intros.
-  rewrite <- H1 in H0; auto. econstructor; split; eauto.
+  inv H0. apply make_cmp_correct; auto.
 (* mulf *)
   InvApproxRegs; SimplVM; inv H0. rewrite <- H2. apply make_mulfimm_correct; auto.
   InvApproxRegs; SimplVM; inv H0. fold (Val.mulf (Vfloat n1) rs#r2).
-- 
cgit