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author | xleroy <xleroy@fca1b0fc-160b-0410-b1d3-a4f43f01ea2e> | 2012-01-14 14:23:26 +0000 |
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committer | xleroy <xleroy@fca1b0fc-160b-0410-b1d3-a4f43f01ea2e> | 2012-01-14 14:23:26 +0000 |
commit | a82c9c0e4a0b8e37c9c3ea5ae99714982563606f (patch) | |
tree | 93b9999698a4cd47ec4cb5fcdcdfd215d62f8e9e /ia32/SelectOp.vp | |
parent | bb8f49c419eb8205ef541edcbe17f4d14aa99564 (diff) | |
download | compcert-a82c9c0e4a0b8e37c9c3ea5ae99714982563606f.tar.gz compcert-a82c9c0e4a0b8e37c9c3ea5ae99714982563606f.zip |
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
Diffstat (limited to 'ia32/SelectOp.vp')
-rw-r--r-- | ia32/SelectOp.vp | 416 |
1 files changed, 416 insertions, 0 deletions
diff --git a/ia32/SelectOp.vp b/ia32/SelectOp.vp new file mode 100644 index 00000000..71dc83bb --- /dev/null +++ b/ia32/SelectOp.vp @@ -0,0 +1,416 @@ +(* *********************************************************************) +(* *) +(* 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. *) +(* *) +(* *********************************************************************) + +(** Instruction selection for operators *) + +(** The instruction selection pass recognizes opportunities for using + combined arithmetic and logical operations and addressing modes + offered by the target processor. For instance, the expression [x + 1] + can take advantage of the "immediate add" instruction of the processor, + and on the PowerPC, the expression [(x >> 6) & 0xFF] can be turned + into a "rotate and mask" instruction. + + This file defines functions for building CminorSel expressions and + statements, especially expressions consisting of operator + applications. These functions examine their arguments to choose + cheaper forms of operators whenever possible. + + For instance, [add e1 e2] will return a CminorSel expression semantically + equivalent to [Eop Oadd (e1 ::: e2 ::: Enil)], but will use a + [Oaddimm] operator if one of the arguments is an integer constant, + or suppress the addition altogether if one of the arguments is the + null integer. In passing, we perform operator reassociation + ([(e + c1) * c2] becomes [(e * c2) + (c1 * c2)]) and a small amount + of constant propagation. + + On top of the "smart constructor" functions defined below, + module [Selection] implements the actual instruction selection pass. +*) + +Require Import Coqlib. +Require Import Maps. +Require Import AST. +Require Import Integers. +Require Import Floats. +Require Import Values. +Require Import Memory. +Require Import Globalenvs. +Require Cminor. +Require Import Op. +Require Import CminorSel. + +Open Local Scope cminorsel_scope. + +(** ** Constants **) + +Definition addrsymbol (id: ident) (ofs: int) := + Eop (Olea (Aglobal id ofs)) Enil. + +Definition addrstack (ofs: int) := + Eop (Olea (Ainstack ofs)) Enil. + +(** ** Integer logical negation *) + +Definition notint (e: expr) := Eop (Oxorimm Int.mone) (e ::: Enil). + +(** ** Boolean negation *) + +Fixpoint notbool (e: expr) {struct e} : expr := + let default := Eop (Ocmp (Ccompuimm Ceq Int.zero)) (e ::: Enil) in + match e with + | Eop (Ointconst n) Enil => + Eop (Ointconst (if Int.eq n Int.zero then Int.one else Int.zero)) Enil + | Eop (Ocmp cond) args => + Eop (Ocmp (negate_condition cond)) args + | Econdition e1 e2 e3 => + Econdition e1 (notbool e2) (notbool e3) + | _ => + default + end. + +(** ** Integer addition and pointer addition *) + +Definition offset_addressing (a: addressing) (ofs: int) : addressing := + match a with + | Aindexed n => Aindexed (Int.add n ofs) + | Aindexed2 n => Aindexed2 (Int.add n ofs) + | Ascaled sc n => Ascaled sc (Int.add n ofs) + | Aindexed2scaled sc n => Aindexed2scaled sc (Int.add n ofs) + | Aglobal id n => Aglobal id (Int.add n ofs) + | Abased id n => Abased id (Int.add n ofs) + | Abasedscaled sc id n => Abasedscaled sc id (Int.add n ofs) + | Ainstack n => Ainstack (Int.add n ofs) + end. + +Nondetfunction addimm (n: int) (e: expr) := + if Int.eq n Int.zero then e else + match e with + | Eop (Ointconst m) Enil => Eop (Ointconst(Int.add n m)) Enil + | Eop (Olea addr) args => Eop (Olea (offset_addressing addr n)) args + | _ => Eop (Olea (Aindexed n)) (e ::: Enil) + end. + +Nondetfunction add (e1: expr) (e2: expr) := + match e1, e2 with + | Eop (Ointconst n1) Enil, t2 => addimm n1 t2 + | t1, Eop (Ointconst n2) Enil => addimm n2 t1 + | Eop (Olea (Aindexed n1)) (t1:::Enil), Eop (Olea (Aindexed n2)) (t2:::Enil) => + Eop (Olea (Aindexed2 (Int.add n1 n2))) (t1:::t2:::Enil) + | Eop (Olea (Aindexed n1)) (t1:::Enil), Eop (Olea (Ascaled sc n2)) (t2:::Enil) => + Eop (Olea (Aindexed2scaled sc (Int.add n1 n2))) (t1:::t2:::Enil) + | Eop (Olea (Ascaled sc n1)) (t1:::Enil), Eop (Olea (Aindexed n2)) (t2:::Enil) => + Eop (Olea (Aindexed2scaled sc (Int.add n1 n2))) (t2:::t1:::Enil) + | Eop (Olea (Aindexed n1)) (t1:::Enil), Eop (Olea (Aglobal id ofs)) Enil => + Eop (Olea (Abased id (Int.add ofs n1))) (t1:::Enil) + | Eop (Olea (Aglobal id ofs)) Enil, Eop (Olea (Aindexed n2)) (t2:::Enil) => + Eop (Olea (Abased id (Int.add ofs n2))) (t2:::Enil) + | Eop (Olea (Ascaled sc n1)) (t1:::Enil), Eop (Olea (Aglobal id ofs)) Enil => + Eop (Olea (Abasedscaled sc id (Int.add ofs n1))) (t1:::Enil) + | Eop (Olea (Aglobal id ofs)) Enil, Eop (Olea (Ascaled sc n2)) (t2:::Enil) => + Eop (Olea (Abasedscaled sc id (Int.add ofs n2))) (t2:::Enil) + | Eop (Olea (Ascaled sc n)) (t1:::Enil), t2 => + Eop (Olea (Aindexed2scaled sc n)) (t2:::t1:::Enil) + | t1, Eop (Olea (Ascaled sc n)) (t2:::Enil) => + Eop (Olea (Aindexed2scaled sc n)) (t1:::t2:::Enil) + | Eop (Olea (Aindexed n)) (t1:::Enil), t2 => + Eop (Olea (Aindexed2 n)) (t1:::t2:::Enil) + | t1, Eop (Olea (Aindexed n)) (t2:::Enil) => + Eop (Olea (Aindexed2 n)) (t1:::t2:::Enil) + | _, _ => + Eop (Olea (Aindexed2 Int.zero)) (e1:::e2:::Enil) + end. + +(** ** Integer and pointer subtraction *) + +Nondetfunction sub (e1: expr) (e2: expr) := + match e1, e2 with + | t1, Eop (Ointconst n2) Enil => addimm (Int.neg n2) t1 + | Eop (Olea (Aindexed n1)) (t1:::Enil), Eop (Olea (Aindexed n2)) (t2:::Enil) => + addimm (Int.sub n1 n2) (Eop Osub (t1:::t2:::Enil)) + | Eop (Olea (Aindexed n1)) (t1:::Enil), t2 => + addimm n1 (Eop Osub (t1:::t2:::Enil)) + | t1, Eop (Olea (Aindexed n2)) (t2:::Enil) => + addimm (Int.neg n2) (Eop Osub (t1:::t2:::Enil)) + | _, _ => + Eop Osub (e1:::e2:::Enil) + end. + +Definition negint (e: expr) := Eop Oneg (e ::: Enil). + +(** ** Immediate shifts *) + +Definition shift_is_scale (n: int) : bool := + Int.eq n (Int.repr 1) || Int.eq n (Int.repr 2) || Int.eq n (Int.repr 3). + +Nondetfunction shlimm (e1: expr) (n: int) := + if Int.eq n Int.zero then e1 else + match e1 with + | Eop (Ointconst n1) Enil => + Eop (Ointconst(Int.shl n1 n)) Enil + | Eop (Oshlimm n1) (t1:::Enil) => + if Int.ltu (Int.add n n1) Int.iwordsize + then Eop (Oshlimm (Int.add n n1)) (t1:::Enil) + else Eop (Oshlimm n) (e1:::Enil) + | Eop (Olea (Aindexed n1)) (t1:::Enil) => + if shift_is_scale n + then Eop (Olea (Ascaled (Int.shl Int.one n) (Int.shl n1 n))) (t1:::Enil) + else Eop (Oshlimm n) (e1:::Enil) + | _ => + if shift_is_scale n + then Eop (Olea (Ascaled (Int.shl Int.one n) Int.zero)) (e1:::Enil) + else Eop (Oshlimm n) (e1:::Enil) + end. + +Nondetfunction shruimm (e1: expr) (n: int) := + if Int.eq n Int.zero then e1 else + match e1 with + | Eop (Ointconst n1) Enil => + Eop (Ointconst(Int.shru n1 n)) Enil + | Eop (Oshruimm n1) (t1:::Enil) => + if Int.ltu (Int.add n n1) Int.iwordsize + then Eop (Oshruimm (Int.add n n1)) (t1:::Enil) + else Eop (Oshruimm n) (e1:::Enil) + | _ => + Eop (Oshruimm n) (e1:::Enil) + end. + +Nondetfunction shrimm (e1: expr) (n: int) := + if Int.eq n Int.zero then e1 else + match e1 with + | Eop (Ointconst n1) Enil => + Eop (Ointconst(Int.shr n1 n)) Enil + | Eop (Oshrimm n1) (t1:::Enil) => + if Int.ltu (Int.add n n1) Int.iwordsize + then Eop (Oshrimm (Int.add n n1)) (t1:::Enil) + else Eop (Oshrimm n) (e1:::Enil) + | _ => + Eop (Oshrimm n) (e1:::Enil) + end. + +(** ** Integer multiply *) + +Definition mulimm_base (n1: int) (e2: expr) := + match Int.one_bits n1 with + | i :: nil => + shlimm e2 i + | i :: j :: nil => + Elet e2 (add (shlimm (Eletvar 0) i) (shlimm (Eletvar 0) j)) + | _ => + Eop (Omulimm n1) (e2:::Enil) + end. + +Nondetfunction mulimm (n1: int) (e2: expr) := + if Int.eq n1 Int.zero then Eop (Ointconst Int.zero) Enil + else if Int.eq n1 Int.one then e2 + else match e2 with + | Eop (Ointconst n2) Enil => Eop (Ointconst(Int.mul n1 n2)) Enil + | Eop (Olea (Aindexed n2)) (t2:::Enil) => addimm (Int.mul n1 n2) (mulimm_base n1 t2) + | _ => mulimm_base n1 e2 + end. + +Nondetfunction mul (e1: expr) (e2: expr) := + match e1, e2 with + | Eop (Ointconst n1) Enil, t2 => mulimm n1 t2 + | t1, Eop (Ointconst n2) Enil => mulimm n2 t1 + | _, _ => Eop Omul (e1:::e2:::Enil) + end. + +(** ** Bitwise and, or, xor *) + +Nondetfunction andimm (n1: int) (e2: expr) := + if Int.eq n1 Int.zero then Eop (Ointconst Int.zero) Enil + else if Int.eq n1 Int.mone then e2 + else match e2 with + | Eop (Ointconst n2) Enil => + Eop (Ointconst (Int.and n1 n2)) Enil + | Eop (Oandimm n2) (t2:::Enil) => + Eop (Oandimm (Int.and n1 n2)) (t2:::Enil) + | Eop Ocast8unsigned (t2:::Enil) => + Eop (Oandimm (Int.and n1 (Int.repr 255))) (t2:::Enil) + | Eop Ocast16unsigned (t2:::Enil) => + Eop (Oandimm (Int.and n1 (Int.repr 65535))) (t2:::Enil) + | _ => + Eop (Oandimm n1) (e2:::Enil) + end. + +Nondetfunction and (e1: expr) (e2: expr) := + match e1, e2 with + | Eop (Ointconst n1) Enil, t2 => andimm n1 t2 + | t1, Eop (Ointconst n2) Enil => andimm n2 t1 + | _, _ => Eop Oand (e1:::e2:::Enil) + end. + +Nondetfunction orimm (n1: int) (e2: expr) := + if Int.eq n1 Int.zero then e2 + else if Int.eq n1 Int.mone then Eop (Ointconst Int.mone) Enil + else match e2 with + | Eop (Ointconst n2) Enil => + Eop (Ointconst (Int.or n1 n2)) Enil + | Eop (Oorimm n2) (t2:::Enil) => + Eop (Oorimm (Int.or n1 n2)) (t2:::Enil) + | _ => + Eop (Oorimm n1) (e2:::Enil) + end. + +Definition same_expr_pure (e1 e2: expr) := + match e1, e2 with + | Evar v1, Evar v2 => if ident_eq v1 v2 then true else false + | _, _ => false + end. + +Nondetfunction or (e1: expr) (e2: expr) := + match e1, e2 with + | Eop (Ointconst n1) Enil, t2 => orimm n1 t2 + | t1, Eop (Ointconst n2) Enil => orimm n2 t1 + | Eop (Oshlimm n1) (t1:::Enil), Eop (Oshruimm n2) (t2:::Enil) => + if Int.eq (Int.add n1 n2) Int.iwordsize + && same_expr_pure t1 t2 + then Eop (Ororimm n2) (t1:::Enil) + else Eop Oor (e1:::e2:::Enil) + | Eop (Oshruimm n2) (t2:::Enil), Eop (Oshlimm n1) (t1:::Enil) => + if Int.eq (Int.add n1 n2) Int.iwordsize + && same_expr_pure t1 t2 + then Eop (Ororimm n2) (t1:::Enil) + else Eop Oor (e1:::e2:::Enil) + | _, _ => + Eop Oor (e1:::e2:::Enil) + end. + +Nondetfunction xorimm (n1: int) (e2: expr) := + if Int.eq n1 Int.zero then e2 + else match e2 with + | Eop (Ointconst n2) Enil => + Eop (Ointconst (Int.xor n1 n2)) Enil + | Eop (Oxorimm n2) (t2:::Enil) => + Eop (Oxorimm (Int.xor n1 n2)) (t2:::Enil) + | _ => + Eop (Oxorimm n1) (e2:::Enil) + end. + +Nondetfunction xor (e1: expr) (e2: expr) := + match e1, e2 with + | Eop (Ointconst n1) Enil, t2 => xorimm n1 t2 + | t1, Eop (Ointconst n2) Enil => xorimm n2 t1 + | _, _ => Eop Oxor (e1:::e2:::Enil) + end. + +(** ** Integer division and modulus *) + +Definition divu (e1: expr) (e2: expr) := Eop Odivu (e1:::e2:::Enil). +Definition modu (e1: expr) (e2: expr) := Eop Omodu (e1:::e2:::Enil). +Definition divs (e1: expr) (e2: expr) := Eop Odiv (e1:::e2:::Enil). +Definition mods (e1: expr) (e2: expr) := Eop Omod (e1:::e2:::Enil). + +(** ** General shifts *) + +Nondetfunction shl (e1: expr) (e2: expr) := + match e2 with + | Eop (Ointconst n2) Enil => shlimm e1 n2 + | _ => Eop Oshl (e1:::e2:::Enil) + end. + +Nondetfunction shr (e1: expr) (e2: expr) := + match e2 with + | Eop (Ointconst n2) Enil => shrimm e1 n2 + | _ => Eop Oshr (e1:::e2:::Enil) + end. + +Nondetfunction shru (e1: expr) (e2: expr) := + match e2 with + | Eop (Ointconst n2) Enil => shruimm e1 n2 + | _ => Eop Oshru (e1:::e2:::Enil) + end. + +(** ** Floating-point arithmetic *) + +Definition negf (e: expr) := Eop Onegf (e ::: Enil). +Definition absf (e: expr) := Eop Oabsf (e ::: Enil). +Definition addf (e1 e2: expr) := Eop Oaddf (e1 ::: e2 ::: Enil). +Definition subf (e1 e2: expr) := Eop Osubf (e1 ::: e2 ::: Enil). +Definition mulf (e1 e2: expr) := Eop Omulf (e1 ::: e2 ::: Enil). +Definition divf (e1 e2: expr) := Eop Odivf (e1 ::: e2 ::: Enil). + +(** ** Comparisons *) + +Nondetfunction comp (c: comparison) (e1: expr) (e2: expr) := + match e1, e2 with + | Eop (Ointconst n1) Enil, t2 => + Eop (Ocmp (Ccompimm (swap_comparison c) n1)) (t2 ::: Enil) + | t1, Eop (Ointconst n2) Enil => + Eop (Ocmp (Ccompimm c n2)) (t1 ::: Enil) + | _, _ => + Eop (Ocmp (Ccomp c)) (e1 ::: e2 ::: Enil) + end. + +Nondetfunction compu (c: comparison) (e1: expr) (e2: expr) := + match e1, e2 with + | Eop (Ointconst n1) Enil, t2 => + Eop (Ocmp (Ccompuimm (swap_comparison c) n1)) (t2 ::: Enil) + | t1, Eop (Ointconst n2) Enil => + Eop (Ocmp (Ccompuimm c n2)) (t1 ::: Enil) + | _, _ => + Eop (Ocmp (Ccompu c)) (e1 ::: e2 ::: Enil) + end. + +Definition compf (c: comparison) (e1: expr) (e2: expr) := + Eop (Ocmp (Ccompf c)) (e1 ::: e2 ::: Enil). + +(** ** Integer conversions *) + +Nondetfunction cast8unsigned (e: expr) := + match e with + | Eop (Oandimm n) (t:::Enil) => + Eop (Oandimm (Int.and (Int.repr 255) n)) (t:::Enil) + | _ => + Eop Ocast8unsigned (e:::Enil) + end. + +Definition cast8signed (e: expr) := Eop Ocast8signed (e ::: Enil). + +Nondetfunction cast16unsigned (e: expr) := + match e with + | Eop (Oandimm n) (t:::Enil) => + Eop (Oandimm (Int.and (Int.repr 65535) n)) (t:::Enil) + | _ => + Eop Ocast16unsigned (e:::Enil) + end. + +Definition cast16signed (e: expr) := Eop Ocast16signed (e ::: Enil). + +(** Floating-point conversions *) + +Definition singleoffloat (e: expr) := Eop Osingleoffloat (e ::: Enil). +Definition intoffloat (e: expr) := Eop Ointoffloat (e ::: Enil). +Definition floatofint (e: expr) := Eop Ofloatofint (e ::: Enil). + +Definition intuoffloat (e: expr) := + let f := Eop (Ofloatconst (Float.floatofintu Float.ox8000_0000)) Enil in + Elet e + (Econdition (CEcond (Ccompf Clt) (Eletvar O ::: f ::: Enil)) + (intoffloat (Eletvar O)) + (addimm Float.ox8000_0000 (intoffloat (subf (Eletvar O) f)))). + +Definition floatofintu (e: expr) := + let f := Eop (Ofloatconst (Float.floatofintu Float.ox8000_0000)) Enil in + Elet e + (Econdition (CEcond (Ccompuimm Clt Float.ox8000_0000) (Eletvar O ::: Enil)) + (floatofint (Eletvar O)) + (addf (floatofint (addimm (Int.neg Float.ox8000_0000) (Eletvar O))) f)). + +(** ** Addressing modes *) + +Nondetfunction addressing (chunk: memory_chunk) (e: expr) := + match e with + | Eop (Olea addr) args => (addr, args) + | _ => (Aindexed Int.zero, e:::Enil) + end. + |