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Diffstat (limited to 'verilog/ConstpropOp.vp')
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diff --git a/verilog/ConstpropOp.vp b/verilog/ConstpropOp.vp new file mode 100644 index 00000000..ada8d54a --- /dev/null +++ b/verilog/ConstpropOp.vp @@ -0,0 +1,434 @@ +(* *********************************************************************) +(* *) +(* The Compcert verified compiler *) +(* *) +(* Xavier Leroy, INRIA Paris *) +(* *) +(* 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. *) +(* *) +(* *********************************************************************) + +(** Strength reduction for operators and conditions. + This is the machine-dependent part of [Constprop]. *) + +Require Import Coqlib Compopts. +Require Import AST Integers Floats. +Require Import Op Registers. +Require Import ValueDomain ValueAOp. + +(** * Converting known values to constants *) + +Parameter symbol_is_external: ident -> bool. (**r See [SelectOp] *) + +Definition Olea_ptr (a: addressing) := if Archi.ptr64 then Oleal a else Olea a. + +Definition const_for_result (a: aval) : option operation := + match a with + | I n => Some(Ointconst n) + | L n => if Archi.ptr64 then Some(Olongconst n) else None + | F n => if Compopts.generate_float_constants tt then Some(Ofloatconst n) else None + | FS n => if Compopts.generate_float_constants tt then Some(Osingleconst n) else None + | Ptr(Gl id ofs) => + if symbol_is_external id then + if Ptrofs.eq ofs Ptrofs.zero then Some (Oindirectsymbol id) else None + else + Some (Olea_ptr (Aglobal id ofs)) + | Ptr(Stk ofs) => Some(Olea_ptr (Ainstack ofs)) + | _ => None + 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. *) + +Nondetfunction cond_strength_reduction + (cond: condition) (args: list reg) (vl: list aval) := + 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) + | Ccompl c, r1 :: r2 :: nil, L n1 :: v2 :: nil => + (Ccomplimm (swap_comparison c) n1, r2 :: nil) + | Ccompl c, r1 :: r2 :: nil, v1 :: L n2 :: nil => + (Ccomplimm c n2, r1 :: nil) + | Ccomplu c, r1 :: r2 :: nil, L n1 :: v2 :: nil => + (Ccompluimm (swap_comparison c) n1, r2 :: nil) + | Ccomplu c, r1 :: r2 :: nil, v1 :: L n2 :: nil => + (Ccompluimm c n2, r1 :: nil) + | _, _, _ => + (cond, args) + end. + +Definition make_cmp_base (c: condition) (args: list reg) (vl: list aval) := + let (c', args') := cond_strength_reduction c args vl in (Ocmp c', args'). + +Definition make_cmp_imm_eq (c: condition) (args: list reg) (vl: list aval) + (n: int) (r1: reg) (v1: aval) := + if Int.eq_dec n Int.one && vincl v1 (Uns Ptop 1) then (Omove, r1 :: nil) + else if Int.eq_dec n Int.zero && vincl v1 (Uns Ptop 1) then (Oxorimm Int.one, r1 :: nil) + else make_cmp_base c args vl. + +Definition make_cmp_imm_ne (c: condition) (args: list reg) (vl: list aval) + (n: int) (r1: reg) (v1: aval) := + if Int.eq_dec n Int.zero && vincl v1 (Uns Ptop 1) then (Omove, r1 :: nil) + else if Int.eq_dec n Int.one && vincl v1 (Uns Ptop 1) then (Oxorimm Int.one, r1 :: nil) + else make_cmp_base c args vl. + +Nondetfunction make_cmp (c: condition) (args: list reg) (vl: list aval) := + match c, args, vl with + | Ccompimm Ceq n, r1 :: nil, v1 :: nil => + make_cmp_imm_eq c args vl n r1 v1 + | Ccompimm Cne n, r1 :: nil, v1 :: nil => + make_cmp_imm_ne c args vl n r1 v1 + | Ccompuimm Ceq n, r1 :: nil, v1 :: nil => + make_cmp_imm_eq c args vl n r1 v1 + | Ccompuimm Cne n, r1 :: nil, v1 :: nil => + make_cmp_imm_ne c args vl n r1 v1 + | _, _, _ => + make_cmp_base c args vl + end. + +Definition make_select (c: condition) (ty: typ) + (r1 r2: reg) (args: list reg) (vl: list aval) := + match resolve_branch (eval_static_condition c vl) with + | Some b => (Omove, (if b then r1 else r2) :: nil) + | None => + let (c', args') := cond_strength_reduction c args vl in + (Osel c' ty, r1 :: r2 :: args') + end. + +(** For addressing modes, we need to distinguish +- reductions that produce pointers (i.e. that produce [Aglobal], [Ainstack], [Abased] and [Abasedscaled] addressing modes), which are valid only if the pointer size is right; +- other reductions (producing [Aindexed] or [Aindexed2] modes), which are valid independently of the pointer size. +*) + +Nondetfunction addr_strength_reduction_32_generic + (addr: addressing) (args: list reg) (vl: list aval) := + match addr, args, vl with + | Aindexed2 ofs, r1 :: r2 :: nil, I n1 :: v2 :: nil => + (Aindexed (Int.signed n1 + ofs), r2 :: nil) + | Aindexed2 ofs, r1 :: r2 :: nil, v1 :: I n2 :: nil => + (Aindexed (Int.signed n2 + ofs), r1 :: nil) + | Aindexed2scaled sc ofs, r1 :: r2 :: nil, v1 :: I n2 :: nil => + (Aindexed (Int.signed n2 * sc + ofs), r1 :: nil) + | Aindexed2scaled sc ofs, r1 :: r2 :: nil, I n1 :: v2 :: nil => + (Ascaled sc (Int.signed n1 + ofs), r2 :: nil) + | _, _ => + (addr, args) + end. + +Nondetfunction addr_strength_reduction_32 + (addr: addressing) (args: list reg) (vl: list aval) := + + if Archi.ptr64 then addr_strength_reduction_32_generic addr args vl else + + match addr, args, vl with + + | Aindexed ofs, r1 :: nil, Ptr(Gl symb n) :: nil => + (Aglobal symb (Ptrofs.add n (Ptrofs.repr ofs)), nil) + | Aindexed ofs, r1 :: nil, Ptr(Stk n) :: nil => + (Ainstack (Ptrofs.add n (Ptrofs.repr ofs)), nil) + + | Aindexed2 ofs, r1 :: r2 :: nil, Ptr(Gl symb n1) :: I n2 :: nil => + (Aglobal symb (Ptrofs.add (Ptrofs.add n1 (Ptrofs.of_int n2)) (Ptrofs.repr ofs)), nil) + | Aindexed2 ofs, r1 :: r2 :: nil, I n1 :: Ptr(Gl symb n2) :: nil => + (Aglobal symb (Ptrofs.add (Ptrofs.add n2 (Ptrofs.of_int n1)) (Ptrofs.repr ofs)), nil) + | Aindexed2 ofs, r1 :: r2 :: nil, Ptr(Stk n1) :: I n2 :: nil => + (Ainstack (Ptrofs.add (Ptrofs.add n1 (Ptrofs.of_int n2)) (Ptrofs.repr ofs)), nil) + | Aindexed2 ofs, r1 :: r2 :: nil, I n1 :: Ptr(Stk n2) :: nil => + (Ainstack (Ptrofs.add (Ptrofs.add (Ptrofs.of_int n1) n2) (Ptrofs.repr ofs)), nil) + | Aindexed2 ofs, r1 :: r2 :: nil, Ptr(Gl symb n1) :: v2 :: nil => + (Abased symb (Ptrofs.add n1 (Ptrofs.repr ofs)), r2 :: nil) + | Aindexed2 ofs, r1 :: r2 :: nil, v1 :: Ptr(Gl symb n2) :: nil => + (Abased symb (Ptrofs.add n2 (Ptrofs.repr ofs)), r1 :: nil) + + | Aindexed2scaled sc ofs, r1 :: r2 :: nil, Ptr(Gl symb n1) :: I n2 :: nil => + (Aglobal symb (Ptrofs.add (Ptrofs.add n1 (Ptrofs.of_int (Int.mul n2 (Int.repr sc)))) (Ptrofs.repr ofs)), nil) + + | Aindexed2scaled sc ofs, r1 :: r2 :: nil, Ptr(Gl symb n1) :: v2 :: nil => + (Abasedscaled sc symb (Ptrofs.add n1 (Ptrofs.repr ofs)), r2 :: nil) + + | Abased id ofs, r1 :: nil, I n1 :: nil => + (Aglobal id (Ptrofs.add ofs (Ptrofs.of_int n1)), nil) + + | Abasedscaled sc id ofs, r1 :: nil, I n1 :: nil => + (Aglobal id (Ptrofs.add ofs (Ptrofs.of_int (Int.mul n1 (Int.repr sc)))), nil) + + | _, _ => + addr_strength_reduction_32_generic addr args vl + end. + +Nondetfunction addr_strength_reduction_64_generic + (addr: addressing) (args: list reg) (vl: list aval) := + match addr, args, vl with + | Aindexed2 ofs, r1 :: r2 :: nil, L n1 :: v2 :: nil => + (Aindexed (Int64.signed n1 + ofs), r2 :: nil) + | Aindexed2 ofs, r1 :: r2 :: nil, v1 :: L n2 :: nil => + (Aindexed (Int64.signed n2 + ofs), r1 :: nil) + | Aindexed2scaled sc ofs, r1 :: r2 :: nil, v1 :: L n2 :: nil => + (Aindexed (Int64.signed n2 * sc + ofs), r1 :: nil) + | Aindexed2scaled sc ofs, r1 :: r2 :: nil, L n1 :: v2 :: nil => + (Ascaled sc (Int64.signed n1 + ofs), r2 :: nil) + | _, _ => + (addr, args) + end. + +Nondetfunction addr_strength_reduction_64 + (addr: addressing) (args: list reg) (vl: list aval) := + + if negb Archi.ptr64 then addr_strength_reduction_64_generic addr args vl else + + match addr, args, vl with + + | Aindexed ofs, r1 :: nil, Ptr(Gl symb n) :: nil => + (Aglobal symb (Ptrofs.add n (Ptrofs.repr ofs)), nil) + | Aindexed ofs, r1 :: nil, Ptr(Stk n) :: nil => + (Ainstack (Ptrofs.add n (Ptrofs.repr ofs)), nil) + + | Aindexed2 ofs, r1 :: r2 :: nil, Ptr(Gl symb n1) :: L n2 :: nil => + (Aglobal symb (Ptrofs.add (Ptrofs.add n1 (Ptrofs.of_int64 n2)) (Ptrofs.repr ofs)), nil) + | Aindexed2 ofs, r1 :: r2 :: nil, L n1 :: Ptr(Gl symb n2) :: nil => + (Aglobal symb (Ptrofs.add (Ptrofs.add n2 (Ptrofs.of_int64 n1)) (Ptrofs.repr ofs)), nil) + | Aindexed2 ofs, r1 :: r2 :: nil, Ptr(Stk n1) :: L n2 :: nil => + (Ainstack (Ptrofs.add (Ptrofs.add n1 (Ptrofs.of_int64 n2)) (Ptrofs.repr ofs)), nil) + | Aindexed2 ofs, r1 :: r2 :: nil, L n1 :: Ptr(Stk n2) :: nil => + (Ainstack (Ptrofs.add (Ptrofs.add (Ptrofs.of_int64 n1) n2) (Ptrofs.repr ofs)), nil) + + | Aindexed2scaled sc ofs, r1 :: r2 :: nil, Ptr(Gl symb n1) :: L n2 :: nil => + (Aglobal symb (Ptrofs.add (Ptrofs.add n1 (Ptrofs.of_int64 (Int64.mul n2 (Int64.repr sc)))) (Ptrofs.repr ofs)), nil) + + | _, _ => + addr_strength_reduction_64_generic addr args vl + end. + +Definition addr_strength_reduction + (addr: addressing) (args: list reg) (vl: list aval) := + let addr_args' := + if Archi.ptr64 + then addr_strength_reduction_64 addr args vl + else addr_strength_reduction_32 addr args vl in + if addressing_valid (fst addr_args') then addr_args' else (addr, args). + +Definition make_addimm (n: int) (r: reg) := + if Int.eq n Int.zero + then (Omove, r :: nil) + else (Olea (Aindexed (Int.signed 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 (Oshlimm 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 (Oshruimm n, r1 :: nil) + else (Oshru, r1 :: r2 :: nil). + +Definition make_mulimm (n: int) (r: reg) := + if Int.eq n Int.zero then + (Ointconst Int.zero, nil) + else if Int.eq n Int.one then + (Omove, r :: nil) + else + match Int.is_power2 n with + | Some l => (Oshlimm l, r :: nil) + | None => (Omulimm n, r :: nil) + end. + +Definition make_andimm (n: int) (r: reg) (a: aval) := + if Int.eq n Int.zero then (Ointconst Int.zero, nil) + else if Int.eq n Int.mone then (Omove, r :: nil) + else if match a with Uns _ m => Int.eq (Int.zero_ext m (Int.not n)) Int.zero + | _ => false end + 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 if Int.eq n Int.mone then (Onot, r :: nil) + else (Oxorimm n, r :: nil). + +Definition make_divimm n (r1 r2: reg) := + if Int.eq n Int.one then + (Omove, r1 :: nil) + else + 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 (r1 r2: reg) := + if Int.eq n Int.one then + (Omove, r1 :: nil) + else + match Int.is_power2 n with + | Some l => (Oshruimm l, r1 :: nil) + | None => (Odivu, r1 :: r2 :: nil) + end. + +Definition make_moduimm n (r1 r2: reg) := + match Int.is_power2 n with + | Some l => (Oandimm (Int.sub n Int.one), r1 :: nil) + | None => (Omodu, r1 :: r2 :: nil) + end. + +Definition make_addlimm (n: int64) (r: reg) := + if Int64.eq n Int64.zero + then (Omove, r :: nil) + else (Oleal (Aindexed (Int64.signed n)), r :: nil). + +Definition make_shllimm (n: int) (r1 r2: reg) := + if Int.eq n Int.zero then (Omove, r1 :: nil) + else if Int.ltu n Int64.iwordsize' then (Oshllimm n, r1 :: nil) + else (Oshll, r1 :: r2 :: nil). + +Definition make_shrlimm (n: int) (r1 r2: reg) := + if Int.eq n Int.zero then (Omove, r1 :: nil) + else if Int.ltu n Int64.iwordsize' then (Oshrlimm n, r1 :: nil) + else (Oshrl, r1 :: r2 :: nil). + +Definition make_shrluimm (n: int) (r1 r2: reg) := + if Int.eq n Int.zero then (Omove, r1 :: nil) + else if Int.ltu n Int64.iwordsize' then (Oshrluimm n, r1 :: nil) + else (Oshrlu, r1 :: r2 :: nil). + +Definition make_mullimm (n: int64) (r: reg) := + if Int64.eq n Int64.zero then + (Olongconst Int64.zero, nil) + else if Int64.eq n Int64.one then + (Omove, r :: nil) + else + match Int64.is_power2' n with + | Some l => (Oshllimm l, r :: nil) + | None => (Omullimm n, r :: nil) + end. + +Definition make_andlimm (n: int64) (r: reg) (a: aval) := + if Int64.eq n Int64.zero then (Olongconst Int64.zero, nil) + else if Int64.eq n Int64.mone then (Omove, r :: nil) + else (Oandlimm n, r :: nil). + +Definition make_orlimm (n: int64) (r: reg) := + if Int64.eq n Int64.zero then (Omove, r :: nil) + else if Int64.eq n Int64.mone then (Olongconst Int64.mone, nil) + else (Oorlimm n, r :: nil). + +Definition make_xorlimm (n: int64) (r: reg) := + if Int64.eq n Int64.zero then (Omove, r :: nil) + else if Int64.eq n Int64.mone then (Onotl, r :: nil) + else (Oxorlimm n, r :: nil). + +Definition make_divlimm n (r1 r2: reg) := + match Int64.is_power2' n with + | Some l => if Int.ltu l (Int.repr 63) + then (Oshrxlimm l, r1 :: nil) + else (Odivl, r1 :: r2 :: nil) + | None => (Odivl, r1 :: r2 :: nil) + end. + +Definition make_divluimm n (r1 r2: reg) := + match Int64.is_power2' n with + | Some l => (Oshrluimm l, r1 :: nil) + | None => (Odivlu, r1 :: r2 :: nil) + end. + +Definition make_modluimm n (r1 r2: reg) := + match Int64.is_power2 n with + | Some l => (Oandlimm (Int64.sub n Int64.one), r1 :: nil) + | None => (Omodlu, r1 :: r2 :: nil) + end. + +Definition make_mulfimm (n: float) (r r1 r2: reg) := + if Float.eq_dec n (Float.of_int (Int.repr 2)) + then (Oaddf, r :: r :: nil) + else (Omulf, r1 :: r2 :: nil). + +Definition make_mulfsimm (n: float32) (r r1 r2: reg) := + if Float32.eq_dec n (Float32.of_int (Int.repr 2)) + then (Oaddfs, r :: r :: nil) + else (Omulfs, r1 :: r2 :: nil). + +Definition make_cast8signed (r: reg) (a: aval) := + if vincl a (Sgn Ptop 8) then (Omove, r :: nil) else (Ocast8signed, r :: nil). +Definition make_cast8unsigned (r: reg) (a: aval) := + if vincl a (Uns Ptop 8) then (Omove, r :: nil) else (Ocast8unsigned, r :: nil). +Definition make_cast16signed (r: reg) (a: aval) := + if vincl a (Sgn Ptop 16) then (Omove, r :: nil) else (Ocast16signed, r :: nil). +Definition make_cast16unsigned (r: reg) (a: aval) := + if vincl a (Uns Ptop 16) then (Omove, r :: nil) else (Ocast16unsigned, r :: nil). + +Nondetfunction op_strength_reduction + (op: operation) (args: list reg) (vl: list aval) := + match op, args, vl with + | Ocast8signed, r1 :: nil, v1 :: nil => make_cast8signed r1 v1 + | Ocast8unsigned, r1 :: nil, v1 :: nil => make_cast8unsigned r1 v1 + | Ocast16signed, r1 :: nil, v1 :: nil => make_cast16signed r1 v1 + | Ocast16unsigned, r1 :: nil, v1 :: nil => make_cast16unsigned r1 v1 + | 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 + | Omul, r1 :: r2 :: nil, v1 :: I n2 :: nil => make_mulimm n2 r1 + | 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 + | Omodu, r1 :: r2 :: nil, v1 :: I n2 :: nil => make_moduimm n2 r1 r2 + | Oand, r1 :: r2 :: nil, I n1 :: v2 :: nil => make_andimm n1 r2 v2 + | Oand, r1 :: r2 :: nil, v1 :: I n2 :: nil => make_andimm n2 r1 v1 + | Oandimm n, r1 :: nil, v1 :: nil => make_andimm n r1 v1 + | 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 + | Olea addr, args, vl => + let (addr', args') := addr_strength_reduction_32 addr args vl in + (Olea addr', args') + | Osubl, r1 :: r2 :: nil, v1 :: L n2 :: nil => make_addlimm (Int64.neg n2) r1 + | Omull, r1 :: r2 :: nil, L n1 :: v2 :: nil => make_mullimm n1 r2 + | Omull, r1 :: r2 :: nil, v1 :: L n2 :: nil => make_mullimm n2 r1 + | Odivl, r1 :: r2 :: nil, v1 :: L n2 :: nil => make_divlimm n2 r1 r2 + | Odivlu, r1 :: r2 :: nil, v1 :: L n2 :: nil => make_divluimm n2 r1 r2 + | Omodlu, r1 :: r2 :: nil, v1 :: L n2 :: nil => make_modluimm n2 r1 r2 + | Oandl, r1 :: r2 :: nil, L n1 :: v2 :: nil => make_andlimm n1 r2 v2 + | Oandl, r1 :: r2 :: nil, v1 :: L n2 :: nil => make_andlimm n2 r1 v1 + | Oandlimm n, r1 :: nil, v1 :: nil => make_andlimm n r1 v1 + | Oorl, r1 :: r2 :: nil, L n1 :: v2 :: nil => make_orlimm n1 r2 + | Oorl, r1 :: r2 :: nil, v1 :: L n2 :: nil => make_orlimm n2 r1 + | Oxorl, r1 :: r2 :: nil, L n1 :: v2 :: nil => make_xorlimm n1 r2 + | Oxorl, r1 :: r2 :: nil, v1 :: L n2 :: nil => make_xorlimm n2 r1 + | Oshll, r1 :: r2 :: nil, v1 :: I n2 :: nil => make_shllimm n2 r1 r2 + | Oshrl, r1 :: r2 :: nil, v1 :: I n2 :: nil => make_shrlimm n2 r1 r2 + | Oshrlu, r1 :: r2 :: nil, v1 :: I n2 :: nil => make_shrluimm n2 r1 r2 + | Oleal addr, args, vl => + let (addr', args') := addr_strength_reduction_64 addr args vl in + (Oleal addr', args') + | Ocmp c, args, vl => make_cmp c args vl + | Osel c ty, r1 :: r2 :: args, v1 :: v2 :: vl => make_select c ty r1 r2 args vl + | Omulf, r1 :: r2 :: nil, v1 :: F n2 :: nil => make_mulfimm n2 r1 r1 r2 + | Omulf, r1 :: r2 :: nil, F n1 :: v2 :: nil => make_mulfimm n1 r2 r1 r2 + | Omulfs, r1 :: r2 :: nil, v1 :: FS n2 :: nil => make_mulfsimm n2 r1 r1 r2 + | Omulfs, r1 :: r2 :: nil, FS n1 :: v2 :: nil => make_mulfsimm n1 r2 r1 r2 + | _, _, _ => (op, args) + end. |