diff options
| author |  xleroy <xleroy@fca1b0fc-160b-0410-b1d3-a4f43f01ea2e> | 2014-04-09 13:26:16 +0000 |
|---|---|---|
| committer | xleroy <xleroy@fca1b0fc-160b-0410-b1d3-a4f43f01ea2e> | 2014-04-09 13:26:16 +0000 |
| commit | 336a1f906a9c617e68e9d43e244bf42e9bdbae64 (patch) | |
| tree | 47c65aa1aa9c9eadbd98ec0e443ad0105bb0b268 /backend/ValueDomain.v | |
| parent | 76f49ca6af4ffbc77c0ba7965d409c3de04011bd (diff) | |
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
Diffstat (limited to 'backend/ValueDomain.v')
| -rw-r--r-- | backend/ValueDomain.v | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/backend/ValueDomain.v b/backend/ValueDomain.v index 239dd47..2ece8cd 100644 --- a/backend/ValueDomain.v +++ b/backend/ValueDomain.v @@ -681,6 +681,14 @@ Qed. Hint Resolve is_uns_mon is_sgn_mon is_uns_sgn is_uns_usize is_sgn_ssize : va. +Lemma is_uns_1: + forall n, is_uns 1 n -> n = Int.zero \/ n = Int.one. +Proof. + intros. destruct (Int.testbit n 0) eqn:B0; [right|left]; apply Int.same_bits_eq; intros. + rewrite Int.bits_one. destruct (zeq i 0). subst i; auto. apply H; omega. + rewrite Int.bits_zero. destruct (zeq i 0). subst i; auto. apply H; omega. +Qed. + (** Smart constructors for [Uns] and [Sgn]. *) Definition uns (n: Z) : aval := @@ -749,6 +757,12 @@ Qed. Hint Resolve vmatch_uns vmatch_uns_undef vmatch_sgn vmatch_sgn_undef : va. +Lemma vmatch_Uns_1: + forall v, vmatch v (Uns 1) -> v = Vundef \/ v = Vint Int.zero \/ v = Vint Int.one. +Proof. + intros. inv H; auto. right. exploit is_uns_1; eauto. intuition congruence. +Qed. + (** Ordering *) Inductive vge: aval -> aval -> Prop := |