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| author | Xavier Leroy <xavier.leroy@inria.fr> | 2016-10-02 16:17:51 +0200 |
|---|---|---|
| committer | Xavier Leroy <xavier.leroy@inria.fr> | 2016-10-02 16:17:51 +0200 |
| commit | f21a6b181dded86ef0e5c7ab94f74e5b960fd510 (patch) | |
| tree | 01bb7b59e438c60d12d87d869b6c890095a977f4 /backend/ValueDomain.v | |
| parent | a14b9578ee5297d954103e05d7b2d322816ddd8f (diff) | |
| download | compcert-kvx-f21a6b181dded86ef0e5c7ab94f74e5b960fd510.tar.gz compcert-kvx-f21a6b181dded86ef0e5c7ab94f74e5b960fd510.zip | |
Improve code generation for 64-bit signed integer division
Implement the 'shift right extended' trick, both in the generic implementation (backend/SplitLong) and in the IA32 port.
Note that now SelectDiv depends on SelectLong, and that some work was moved from SelectLong to SelectDiv.
Diffstat (limited to 'backend/ValueDomain.v')
| -rw-r--r-- | backend/ValueDomain.v | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/backend/ValueDomain.v b/backend/ValueDomain.v index 6b314904..bf88a450 100644 --- a/backend/ValueDomain.v +++ b/backend/ValueDomain.v @@ -1938,6 +1938,22 @@ Proof. inv H; inv H0; auto with va. simpl. rewrite E. constructor. Qed. +Definition shrxl (v w: aval) := + match v, w with + | L i, I j => if Int.ltu j (Int.repr 63) then L(Int64.shrx' i j) else ntop + | _, _ => ntop1 v + end. + +Lemma shrxl_sound: + forall v w u x y, vmatch v x -> vmatch w y -> Val.shrxl v w = Some u -> vmatch u (shrxl x y). +Proof. + intros. + destruct v; destruct w; try discriminate; simpl in H1. + destruct (Int.ltu i0 (Int.repr 63)) eqn:LTU; inv H1. + unfold shrxl; inv H; auto with va; inv H0; auto with va. + rewrite LTU; auto with va. +Qed. + (** Floating-point arithmetic operations *) Definition negf := unop_float Float.neg. @@ -4544,7 +4560,7 @@ Hint Resolve cnot_sound symbol_address_sound shll_sound shrl_sound shrlu_sound andl_sound orl_sound xorl_sound notl_sound roll_sound rorl_sound negl_sound addl_sound subl_sound mull_sound - divls_sound divlu_sound modls_sound modlu_sound + divls_sound divlu_sound modls_sound modlu_sound shrxl_sound negf_sound absf_sound addf_sound subf_sound mulf_sound divf_sound negfs_sound absfs_sound |