Strength reduction for operators and conditions.
This is the machine-dependent part of Constprop.
.
.
.
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.
Original definition:
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.
Original definition:
Nondetfunction make_cmp (c: condition) (args: list reg) (vl: list aval) :=
match c, args, vl with
| Ccompimm Ceq n, r1 :: nil, v1 :: nil =>
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
| Ccompimm Cne n, r1 :: nil, v1 :: nil =>
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
| Ccompuimm Ceq n, r1 :: nil, v1 :: nil =>
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 if is_an_integer v1 then make_cmp_base (Ccompimm Ceq n) args vl
else make_cmp_base c args vl
| Ccompuimm Cne n, r1 :: nil, v1 :: nil =>
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 if is_an_integer v1 then make_cmp_base (Ccompimm Cne n) args vl
else make_cmp_base c args vl
| _, _, _ =>
make_cmp_base c args vl
end.
).
Original definition:
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
| Ocast16signed, r1 :: nil, v1 :: nil => make_cast16signed r1 v1
| Oadd, r1 :: r2 :: nil, I n1 :: v2 :: nil => make_addimm n1 r2
| Oadd, r1 :: r2 :: nil, v1 :: I n2 :: nil => make_addimm n2 r1
| Oadd, r1 :: r2 :: nil, Ptr(Gl s n1) :: v2 :: nil => (Oaddsymbol s n1, r2 :: nil)
| Oadd, r1 :: r2 :: nil, v1 :: Ptr(Gl s n1) :: nil => (Oaddsymbol s n1, r1 :: nil)
| 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 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
| Oaddl, r1 :: r2 :: nil, L n1 :: v2 :: nil => make_addlimm n1 r2
| Oaddl, r1 :: r2 :: nil, v1 :: L n2 :: nil => make_addlimm n2 r1
| 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 r1
| Omull, r1 :: r2 :: nil, v1 :: L n2 :: nil => make_mullimm n2 r1 r2
| 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
| 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
| 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.
Original definition:
Nondetfunction addr_strength_reduction
(addr: addressing) (args: list reg) (vl: list aval) :=
match addr, args, vl with
| Aindexed2, r1 :: r2 :: nil, Ptr(Gl symb n1) :: I n2 :: nil =>
(Aglobal symb (Ptrofs.add n1 (Ptrofs.of_int n2)), nil)
| Aindexed2, r1 :: r2 :: nil, I n1 :: Ptr(Gl symb n2) :: nil =>
(Aglobal symb (Ptrofs.add (Ptrofs.of_int n1) n2), nil)
| Aindexed2, r1 :: r2 :: nil, Ptr(Stk n1) :: I n2 :: nil =>
(Ainstack (Ptrofs.add n1 (Ptrofs.of_int n2)), nil)
| Aindexed2, r1 :: r2 :: nil, I n1 :: Ptr(Stk n2) :: nil =>
(Ainstack (Ptrofs.add (Ptrofs.of_int n1) n2), nil)
| Aindexed2, r1 :: r2 :: nil, Ptr(Gl symb n1) :: v2 :: nil =>
(Abased symb n1, r2 :: nil)
| Aindexed2, r1 :: r2 :: nil, v1 :: Ptr(Gl 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 (Ptrofs.add ofs (Ptrofs.of_int n1)), nil)
| Aindexed n, r1 :: nil, Ptr(Gl symb n1) :: nil =>
(Aglobal symb (Ptrofs.add n1 (Ptrofs.of_int n)), nil)
| Aindexed n, r1 :: nil, Ptr(Stk n1) :: nil =>
(Ainstack (Ptrofs.add n1 (Ptrofs.of_int n)), nil)
| _, _, _ =>
(addr, args)
end.