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# 2 "asmcomp/riscv/selection.ml"
(**************************************************************************)
(* *)
(* OCaml *)
(* *)
(* Nicolas Ojeda Bar <n.oje.bar@gmail.com> *)
(* *)
(* Copyright 2016 Institut National de Recherche en Informatique et *)
(* en Automatique. *)
(* *)
(* All rights reserved. This file is distributed under the terms of *)
(* the GNU Lesser General Public License version 2.1, with the *)
(* special exception on linking described in the file LICENSE. *)
(* *)
(**************************************************************************)
(* Instruction selection for the RISC-V processor *)
open Cmm
open Arch
open Mach
(* Instruction selection *)
class selector = object
inherit Selectgen.selector_generic as super
(* RISC-V does not support immediate operands for comparison operators *)
method is_immediate_test _cmp _n = false
method! is_immediate op n =
match op with
| Iadd | Iand | Ior | Ixor -> is_immediate n
(* sub immediate is turned into add immediate opposite *)
| Isub -> is_immediate (-n)
| _ -> super#is_immediate op n
method select_addressing _ = function
| Cop(Cadda, [arg; Cconst_int (n, _)], _) when is_immediate n ->
(Iindexed n, arg)
| Cop(Cadda, [arg1; Cop(Caddi, [arg2; Cconst_int (n, _)], _)], dbg)
when is_immediate n ->
(Iindexed n, Cop(Caddi, [arg1; arg2], dbg))
| arg ->
(Iindexed 0, arg)
method! select_operation op args dbg =
match (op, args) with
(* Recognize (neg-)mult-add and (neg-)mult-sub instructions *)
| (Caddf, [Cop(Cmulf, [arg1; arg2], _); arg3])
| (Caddf, [arg3; Cop(Cmulf, [arg1; arg2], _)]) ->
(Ispecific (Imultaddf false), [arg1; arg2; arg3])
| (Csubf, [Cop(Cmulf, [arg1; arg2], _); arg3]) ->
(Ispecific (Imultsubf false), [arg1; arg2; arg3])
| (Cnegf, [Cop(Csubf, [Cop(Cmulf, [arg1; arg2], _); arg3], _)]) ->
(Ispecific (Imultsubf true), [arg1; arg2; arg3])
| (Cnegf, [Cop(Caddf, [Cop(Cmulf, [arg1; arg2], _); arg3], _)]) ->
(Ispecific (Imultaddf true), [arg1; arg2; arg3])
| (Cstore (Word_int | Word_val as memory_chunk, Assignment), [arg1; arg2]) ->
(* Use trivial addressing mode for non-initializing stores *)
(Istore (memory_chunk, Iindexed 0, true), [arg2; arg1])
| _ ->
super#select_operation op args dbg
end
let fundecl ~future_funcnames f =
(new selector)#emit_fundecl ~future_funcnames f
|
