From a82c9c0e4a0b8e37c9c3ea5ae99714982563606f Mon Sep 17 00:00:00 2001 From: xleroy Date: Sat, 14 Jan 2012 14:23:26 +0000 Subject: Merge of the nonstrict-ops branch: - Most RTL operators now evaluate to Some Vundef instead of None when undefined behavior occurs. - More aggressive instruction selection. - "Bertotization" of pattern-matchings now implemented by a proper preprocessor. - Cast optimization moved to cfrontend/Cminorgen; removed backend/CastOptim. git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@1790 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e --- powerpc/ConstpropOp.vp | 277 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 277 insertions(+) create mode 100644 powerpc/ConstpropOp.vp (limited to 'powerpc/ConstpropOp.vp') diff --git a/powerpc/ConstpropOp.vp b/powerpc/ConstpropOp.vp new file mode 100644 index 00000000..22e89e31 --- /dev/null +++ b/powerpc/ConstpropOp.vp @@ -0,0 +1,277 @@ +(* *********************************************************************) +(* *) +(* 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. *) +(* *) +(* *********************************************************************) + +(** Static analysis and strength reduction for operators + and conditions. This is the machine-dependent part of [Constprop]. *) + +Require Import Coqlib. +Require Import AST. +Require Import Integers. +Require Import Floats. +Require Import Values. +Require Import Op. +Require Import Registers. + +(** * Static analysis *) + +(** To each pseudo-register at each program point, the static analysis + associates a compile-time approximation taken from the following set. *) + +Inductive approx : Type := + | Novalue: approx (** No value possible, code is unreachable. *) + | Unknown: approx (** All values are possible, + no compile-time information is available. *) + | I: int -> approx (** A known integer value. *) + | F: float -> approx (** A known floating-point value. *) + | G: ident -> int -> approx + (** The value is the address of the given global + symbol plus the given integer offset. *) + | S: int -> approx. (** The value is the stack pointer plus the offset. *) + +(** We now define the abstract interpretations of conditions and operators + over this set of approximations. For instance, the abstract interpretation + of the operator [Oaddf] applied to two expressions [a] and [b] is + [F(Float.add f g)] if [a] and [b] have static approximations [Vfloat f] + and [Vfloat g] respectively, and [Unknown] otherwise. + + The static approximations are defined by large pattern-matchings over + the approximations of the results. We write these matchings in the + indirect style described in file [SelectOp] to avoid excessive + duplication of cases in proofs. *) + +Nondetfunction eval_static_condition (cond: condition) (vl: list approx) := + match cond, vl with + | Ccomp c, I n1 :: I n2 :: nil => Some(Int.cmp c n1 n2) + | Ccompu c, I n1 :: I n2 :: nil => Some(Int.cmpu c n1 n2) + | Ccompimm c n, I n1 :: nil => Some(Int.cmp c n1 n) + | Ccompuimm c n, I n1 :: nil => Some(Int.cmpu c n1 n) + | Ccompf c, F n1 :: F n2 :: nil => Some(Float.cmp c n1 n2) + | Cnotcompf c, F n1 :: F n2 :: nil => Some(negb(Float.cmp c n1 n2)) + | Cmaskzero n, I n1 :: nil => Some(Int.eq (Int.and n1 n) Int.zero) + | Cmasknotzero n, I n1::nil => Some(negb(Int.eq (Int.and n1 n) Int.zero)) + | _, _ => None + end. + +Definition eval_static_condition_val (cond: condition) (vl: list approx) := + match eval_static_condition cond vl with + | None => Unknown + | Some b => I(if b then Int.one else Int.zero) + end. + +Definition eval_static_intoffloat (f: float) := + match Float.intoffloat f with Some x => I x | None => Unknown end. + +Nondetfunction eval_static_operation (op: operation) (vl: list approx) := + match op, vl with + | Omove, v1::nil => v1 + | Ointconst n, nil => I n + | Ofloatconst n, nil => F n + | Oaddrsymbol s n, nil => G s n + | Oaddrstack n, nil => S n + | Ocast8signed, I n1 :: nil => I(Int.sign_ext 8 n1) + | Ocast16signed, I n1 :: nil => I(Int.sign_ext 16 n1) + | Oadd, I n1 :: I n2 :: nil => I(Int.add n1 n2) + | Oadd, G s1 n1 :: I n2 :: nil => G s1 (Int.add n1 n2) + | Oadd, I n1 :: G s2 n2 :: nil => G s2 (Int.add n1 n2) + | Oadd, S n1 :: I n2 :: nil => S (Int.add n1 n2) + | Oadd, I n1 :: S n2 :: nil => S (Int.add n1 n2) + | Oaddimm n, I n1 :: nil => I (Int.add n1 n) + | Oaddimm n, G s1 n1 :: nil => G s1 (Int.add n1 n) + | Oaddimm n, S n1 :: nil => S (Int.add n1 n) + | Osub, I n1 :: I n2 :: nil => I(Int.sub n1 n2) + | Osub, G s1 n1 :: I n2 :: nil => G s1 (Int.sub n1 n2) + | Osub, S n1 :: I n2 :: nil => S (Int.sub n1 n2) + | Osubimm n, I n1 :: nil => I (Int.sub n n1) + | Omul, I n1 :: I n2 :: nil => I(Int.mul n1 n2) + | Omulimm n, I n1 :: nil => I(Int.mul n1 n) + | Odiv, I n1 :: I n2 :: nil => if Int.eq n2 Int.zero then Unknown else I(Int.divs n1 n2) + | Odivu, I n1 :: I n2 :: nil => if Int.eq n2 Int.zero then Unknown else I(Int.divu n1 n2) + | Oand, I n1 :: I n2 :: nil => I(Int.and n1 n2) + | Oandimm n, I n1 :: nil => I(Int.and n1 n) + | Oor, I n1 :: I n2 :: nil => I(Int.or n1 n2) + | Oorimm n, I n1 :: nil => I(Int.or n1 n) + | Oxor, I n1 :: I n2 :: nil => I(Int.xor n1 n2) + | Oxorimm n, I n1 :: nil => I(Int.xor n1 n) + | Onand, I n1 :: I n2 :: nil => I(Int.xor (Int.and n1 n2) Int.mone) + | Onor, I n1 :: I n2 :: nil => I(Int.xor (Int.or n1 n2) Int.mone) + | Onxor, I n1 :: I n2 :: nil => I(Int.xor (Int.xor n1 n2) Int.mone) + | Oshl, I n1 :: I n2 :: nil => if Int.ltu n2 Int.iwordsize then I(Int.shl n1 n2) else Unknown + | Oshr, I n1 :: I n2 :: nil => if Int.ltu n2 Int.iwordsize then I(Int.shr n1 n2) else Unknown + | Oshrimm n, I n1 :: nil => if Int.ltu n Int.iwordsize then I(Int.shr n1 n) else Unknown + | Oshrximm n, I n1 :: nil => if Int.ltu n (Int.repr 31) then I(Int.shrx n1 n) else Unknown + | Oshru, I n1 :: I n2 :: nil => if Int.ltu n2 Int.iwordsize then I(Int.shru n1 n2) else Unknown + | Orolm amount mask, I n1 :: nil => I(Int.rolm n1 amount mask) + | Oroli amount mask, I n1 :: I n2 :: nil => I(Int.or (Int.and n1 (Int.not mask)) (Int.rolm n2 amount mask)) + | Onegf, F n1 :: nil => F(Float.neg n1) + | Oabsf, F n1 :: nil => F(Float.abs n1) + | Oaddf, F n1 :: F n2 :: nil => F(Float.add n1 n2) + | Osubf, F n1 :: F n2 :: nil => F(Float.sub n1 n2) + | Omulf, F n1 :: F n2 :: nil => F(Float.mul n1 n2) + | Odivf, F n1 :: F n2 :: nil => F(Float.div n1 n2) + | Omuladdf, F n1 :: F n2 :: F n3 :: nil => F(Float.add (Float.mul n1 n2) n3) + | Omulsubf, F n1 :: F n2 :: F n3 :: nil => F(Float.sub (Float.mul n1 n2) n3) + | Osingleoffloat, F n1 :: nil => F(Float.singleoffloat n1) + | Ointoffloat, F n1 :: nil => eval_static_intoffloat n1 + | Ofloatofwords, I n1 :: I n2 :: nil => F(Float.from_words n1 n2) + | Ocmp c, vl => eval_static_condition_val c vl + | _, _ => Unknown + end. + +(** * Operator strength reduction *) + +(** We now define auxiliary functions for strength reduction of + operators and addressing modes: replacing an operator with a cheaper + one if some of its arguments are statically known. These are again + large pattern-matchings expressed in indirect style. *) + +Section STRENGTH_REDUCTION. + +Nondetfunction cond_strength_reduction + (cond: condition) (args: list reg) (vl: list approx) := + match cond, args, vl with + | Ccomp c, r1 :: r2 :: nil, I n1 :: v2 :: nil => + (Ccompimm (swap_comparison c) n1, r2 :: nil) + | Ccomp c, r1 :: r2 :: nil, v1 :: I n2 :: nil => + (Ccompimm c n2, r1 :: nil) + | Ccompu c, r1 :: r2 :: nil, I n1 :: v2 :: nil => + (Ccompuimm (swap_comparison c) n1, r2 :: nil) + | Ccompu c, r1 :: r2 :: nil, v1 :: I n2 :: nil => + (Ccompuimm c n2, r1 :: nil) + | _, _, _ => + (cond, args) + end. + +Definition make_addimm (n: int) (r: reg) := + if Int.eq n Int.zero + then (Omove, r :: nil) + else (Oaddimm n, r :: nil). + +Definition make_shlimm (n: int) (r1 r2: reg) := + if Int.eq n Int.zero then + (Omove, r1 :: nil) + else if Int.ltu n Int.iwordsize then + (Orolm n (Int.shl Int.mone n), r1 :: nil) + else + (Oshl, r1 :: r2 :: nil). + +Definition make_shrimm (n: int) (r1 r2: reg) := + if Int.eq n Int.zero then + (Omove, r1 :: nil) + else if Int.ltu n Int.iwordsize then + (Oshrimm n, r1 :: nil) + else + (Oshr, r1 :: r2 :: nil). + +Definition make_shruimm (n: int) (r1 r2: reg) := + if Int.eq n Int.zero then + (Omove, r1 :: nil) + else if Int.ltu n Int.iwordsize then + (Orolm (Int.sub Int.iwordsize n) (Int.shru Int.mone n), r1 :: nil) + else + (Oshru, r1 :: r2 :: nil). + +Definition make_mulimm (n: int) (r1 r2: reg) := + if Int.eq n Int.zero then + (Ointconst Int.zero, nil) + else if Int.eq n Int.one then + (Omove, r1 :: nil) + else + match Int.is_power2 n with + | Some l => (Orolm l (Int.shl Int.mone l), r1 :: nil) + | None => (Omulimm n, r1 :: nil) + end. + +Definition make_divimm (n: int) (r1 r2: reg) := + match Int.is_power2 n with + | Some l => if Int.ltu l (Int.repr 31) + then (Oshrximm l, r1 :: nil) + else (Odiv, r1 :: r2 :: nil) + | None => (Odiv, r1 :: r2 :: nil) + end. + +Definition make_divuimm (n: int) (r1 r2: reg) := + match Int.is_power2 n with + | Some l => (Orolm (Int.sub Int.iwordsize l) (Int.shru Int.mone l), r1 :: nil) + | None => (Odivu, r1 :: r2 :: nil) + end. + +Definition make_andimm (n: int) (r: reg) := + if Int.eq n Int.zero + then (Ointconst Int.zero, nil) + else if Int.eq n Int.mone then (Omove, r :: nil) + else (Oandimm n, r :: nil). + +Definition make_orimm (n: int) (r: reg) := + if Int.eq n Int.zero then (Omove, r :: nil) + else if Int.eq n Int.mone then (Ointconst Int.mone, nil) + else (Oorimm n, r :: nil). + +Definition make_xorimm (n: int) (r: reg) := + if Int.eq n Int.zero + then (Omove, r :: nil) + else (Oxorimm n, r :: nil). + +Nondetfunction op_strength_reduction + (op: operation) (args: list reg) (vl: list approx) := + match op, args, vl with + | Oadd, r1 :: r2 :: nil, I n1 :: v2 :: nil => make_addimm n1 r2 + | Oadd, r1 :: r2 :: nil, v1 :: I n2 :: nil => make_addimm n2 r1 + | Osub, r1 :: r2 :: nil, I n1 :: v2 :: nil => (Osubimm n1, r2 :: nil) + | Osub, r1 :: r2 :: nil, v1 :: I n2 :: nil => make_addimm (Int.neg n2) r1 + | Omul, r1 :: r2 :: nil, I n1 :: v2 :: nil => make_mulimm n1 r2 r1 + | Omul, r1 :: r2 :: nil, v1 :: I n2 :: nil => make_mulimm n2 r1 r2 + | Odiv, r1 :: r2 :: nil, v1 :: I n2 :: nil => make_divimm n2 r1 r2 + | Odivu, r1 :: r2 :: nil, v1 :: I n2 :: nil => make_divuimm n2 r1 r2 + | Oand, r1 :: r2 :: nil, I n1 :: v2 :: nil => make_andimm n1 r2 + | Oand, r1 :: r2 :: nil, v1 :: I n2 :: nil => make_andimm n2 r1 + | Oor, r1 :: r2 :: nil, I n1 :: v2 :: nil => make_orimm n1 r2 + | Oor, r1 :: r2 :: nil, v1 :: I n2 :: nil => make_orimm n2 r1 + | Oxor, r1 :: r2 :: nil, I n1 :: v2 :: nil => make_xorimm n1 r2 + | Oxor, r1 :: r2 :: nil, v1 :: I n2 :: nil => make_xorimm n2 r1 + | Oshl, r1 :: r2 :: nil, v1 :: I n2 :: nil => make_shlimm n2 r1 r2 + | Oshr, r1 :: r2 :: nil, v1 :: I n2 :: nil => make_shrimm n2 r1 r2 + | Oshru, r1 :: r2 :: nil, v1 :: I n2 :: nil => make_shruimm n2 r1 r2 + | Ocmp c, args, vl => + let (c', args') := cond_strength_reduction c args vl in (Ocmp c', args') + | _, _, _ => (op, args) + end. + +Nondetfunction addr_strength_reduction + (addr: addressing) (args: list reg) (vl: list approx) := + match addr, args, vl with + | Aindexed2, r1 :: r2 :: nil, G symb n1 :: I n2 :: nil => + (Aglobal symb (Int.add n1 n2), nil) + | Aindexed2, r1 :: r2 :: nil, I n1 :: G symb n2 :: nil => + (Aglobal symb (Int.add n1 n2), nil) + | Aindexed2, r1 :: r2 :: nil, S n1 :: I n2 :: nil => + (Ainstack (Int.add n1 n2), nil) + | Aindexed2, r1 :: r2 :: nil, I n1 :: S n2 :: nil => + (Ainstack (Int.add n1 n2), nil) + | Aindexed2, r1 :: r2 :: nil, G symb n1 :: v2 :: nil => + (Abased symb n1, r2 :: nil) + | Aindexed2, r1 :: r2 :: nil, v1 :: G symb n2 :: nil => + (Abased symb n2, r1 :: nil) + | Aindexed2, r1 :: r2 :: nil, I n1 :: v2 :: nil => + (Aindexed n1, r2 :: nil) + | Aindexed2, r1 :: r2 :: nil, v1 :: I n2 :: nil => + (Aindexed n2, r1 :: nil) + | Abased symb ofs, r1 :: nil, I n1 :: nil => + (Aglobal symb (Int.add ofs n1), nil) + | Aindexed n, r1 :: nil, G symb n1 :: nil => + (Aglobal symb (Int.add n1 n), nil) + | Aindexed n, r1 :: nil, S n1 :: nil => + (Ainstack (Int.add n1 n), nil) + | _, _, _ => + (addr, args) + end. + +End STRENGTH_REDUCTION. -- cgit