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authorBjörn Gustavsson <[email protected]>2018-11-21 10:11:33 +0100
committerGitHub <[email protected]>2018-11-21 10:11:33 +0100
commitee3c9d55b2a483df5a4650ab6e3ef2bbf6b0b090 (patch)
tree4b134cd2bb3ef23a6d81a1ce9211647c513c9f37 /lib
parenteabd949074124d722fb291d0a8877c1ec6544834 (diff)
parente79e5f194577d6c5b289415ec84338f70d2486db (diff)
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Merge pull request #2023 from bjorng/bjorn/compiler/misc-improvements
Enhance compiler optimizations
Diffstat (limited to 'lib')
-rw-r--r--lib/compiler/src/beam_block.erl38
-rw-r--r--lib/compiler/src/beam_ssa.erl1
-rw-r--r--lib/compiler/src/beam_ssa_codegen.erl39
-rw-r--r--lib/compiler/src/beam_ssa_pre_codegen.erl4
4 files changed, 76 insertions, 6 deletions
diff --git a/lib/compiler/src/beam_block.erl b/lib/compiler/src/beam_block.erl
index 9d8d5b2b0c..707974b2c1 100644
--- a/lib/compiler/src/beam_block.erl
+++ b/lib/compiler/src/beam_block.erl
@@ -22,7 +22,7 @@
-module(beam_block).
-export([module/2]).
--import(lists, [reverse/1,splitwith/2]).
+-import(lists, [keysort/2,reverse/1,splitwith/2]).
-spec module(beam_utils:module_code(), [compile:option()]) ->
{'ok',beam_utils:module_code()}.
@@ -53,7 +53,8 @@ blockify([I|Is0]=IsAll, Acc) ->
case collect(I) of
error -> blockify(Is0, [I|Acc]);
Instr when is_tuple(Instr) ->
- {Block,Is} = collect_block(IsAll),
+ {Block0,Is} = collect_block(IsAll),
+ Block = sort_moves(Block0),
blockify(Is, [{block,Block}|Acc])
end;
blockify([], Acc) -> reverse(Acc).
@@ -117,3 +118,36 @@ embed_lines([{block,B1},{line,_}=Line|T], Acc) ->
embed_lines([I|Is], Acc) ->
embed_lines(Is, [I|Acc]);
embed_lines([], Acc) -> Acc.
+
+%% sort_moves([Instruction]) -> [Instruction].
+%% Sort move instructions on the Y register to give the loader
+%% more opportunities for combining instructions.
+
+sort_moves([{set,[{x,_}],[{y,_}],move}=I|Is0]) ->
+ {Moves,Is} = sort_moves_1(Is0, x, y, [I]),
+ Moves ++ sort_moves(Is);
+sort_moves([{set,[{y,_}],[{x,_}],move}=I|Is0]) ->
+ {Moves,Is} = sort_moves_1(Is0, y, x, [I]),
+ Moves ++ sort_moves(Is);
+sort_moves([I|Is]) ->
+ [I|sort_moves(Is)];
+sort_moves([]) -> [].
+
+sort_moves_1([{set,[{x,0}],[_],move}=I|Is], _DTag, _STag, Acc) ->
+ %% The loader sometimes combines a move to x0 with the
+ %% instruction that follows, producing, for example, a move_call
+ %% instruction. Therefore, we don't want include this move
+ %% instruction in the sorting.
+ {sort_on_yreg(Acc)++[I],Is};
+sort_moves_1([{set,[{DTag,_}],[{STag,_}],move}=I|Is], DTag, STag, Acc) ->
+ sort_moves_1(Is, DTag, STag, [I|Acc]);
+sort_moves_1(Is, _DTag, _STag, Acc) ->
+ {sort_on_yreg(Acc),Is}.
+
+sort_on_yreg([{set,[Dst],[Src],move}|_]=Moves) ->
+ case {Dst,Src} of
+ {{y,_},{x,_}} ->
+ keysort(2, Moves);
+ {{x,_},{y,_}} ->
+ keysort(3, Moves)
+ end.
diff --git a/lib/compiler/src/beam_ssa.erl b/lib/compiler/src/beam_ssa.erl
index c5e23d2ae0..b491e340b7 100644
--- a/lib/compiler/src/beam_ssa.erl
+++ b/lib/compiler/src/beam_ssa.erl
@@ -194,6 +194,7 @@ no_side_effect(#b_set{op=Op}) ->
extract -> true;
get_hd -> true;
get_tl -> true;
+ get_map_element -> true;
get_tuple_element -> true;
has_map_field -> true;
is_nonempty_list -> true;
diff --git a/lib/compiler/src/beam_ssa_codegen.erl b/lib/compiler/src/beam_ssa_codegen.erl
index 3c14062d0b..d3facc5911 100644
--- a/lib/compiler/src/beam_ssa_codegen.erl
+++ b/lib/compiler/src/beam_ssa_codegen.erl
@@ -747,7 +747,16 @@ need_live_anno(Op) ->
end.
%%%
-%%% Add annotations for defined Y registers.
+%%% Add the following annotations for Y registers:
+%%%
+%%% def_yregs An ordset with variables that refer to live Y registers.
+%%% That is, Y registers that that have been killed
+%%% are not included. This annotation is added to all
+%%% instructions that require Y registers to be initialized.
+%%%
+%%% kill_yregs This annotation is added to call instructions. It is
+%%% an ordset containing variables referring to Y registers
+%%% that will no longer be used after the call instruction.
%%%
defined(Linear, #cg{regs=Regs}) ->
@@ -863,13 +872,35 @@ opt_allocate(Linear, #cg{regs=Regs}) ->
opt_allocate_1([{L,#cg_blk{is=[#cg_alloc{stack=Stk}=I0|Is]}=Blk0}|Bs]=Bs0, Regs)
when is_integer(Stk) ->
- Yregs = opt_alloc_def(Bs0, gb_sets:singleton(L), []),
- I = I0#cg_alloc{def_yregs=Yregs},
- [{L,Blk0#cg_blk{is=[I|Is]}}|opt_allocate_1(Bs, Regs)];
+ %% Collect the variables that are initialized by copy
+ %% instruction in this block.
+ case ordsets:from_list(opt_allocate_defs(Is, Regs)) of
+ Yregs when length(Yregs) =:= Stk ->
+ %% Those copy instructions are sufficient to fully
+ %% initialize the stack frame.
+ I = I0#cg_alloc{def_yregs=Yregs},
+ [{L,Blk0#cg_blk{is=[I|Is]}}|opt_allocate_1(Bs, Regs)];
+ Yregs0 ->
+ %% Determine a conservative approximation of the Y
+ %% registers that are guaranteed to be initialized by all
+ %% successors of this block, and to it add the variables
+ %% initialized by copy instructions in this block.
+ Yregs1 = opt_alloc_def(Bs0, gb_sets:singleton(L), []),
+ Yregs = ordsets:union(Yregs0, Yregs1),
+ I = I0#cg_alloc{def_yregs=Yregs},
+ [{L,Blk0#cg_blk{is=[I|Is]}}|opt_allocate_1(Bs, Regs)]
+ end;
opt_allocate_1([B|Bs], Regs) ->
[B|opt_allocate_1(Bs, Regs)];
opt_allocate_1([], _) -> [].
+opt_allocate_defs([#cg_set{op=copy,dst=Dst}|Is], Regs) ->
+ case is_yreg(Dst, Regs) of
+ true -> [Dst|opt_allocate_defs(Is, Regs)];
+ false -> []
+ end;
+opt_allocate_defs(_, _Regs) -> [].
+
opt_alloc_def([{L,#cg_blk{is=Is,last=Last}}|Bs], Ws0, Def0) ->
case gb_sets:is_member(L, Ws0) of
false ->
diff --git a/lib/compiler/src/beam_ssa_pre_codegen.erl b/lib/compiler/src/beam_ssa_pre_codegen.erl
index c60c6da9ea..32232e9b9f 100644
--- a/lib/compiler/src/beam_ssa_pre_codegen.erl
+++ b/lib/compiler/src/beam_ssa_pre_codegen.erl
@@ -1478,6 +1478,10 @@ copy_retval_is([#b_set{op=put_tuple_elements,args=Args0}=I0], false, _Yregs,
Copy, Count, Acc) ->
I = I0#b_set{args=copy_sub_args(Args0, Copy)},
{reverse(Acc, [I|acc_copy([], Copy)]),Count};
+copy_retval_is([#b_set{op=Op}=I0], false, Yregs, Copy, Count0, Acc0)
+ when Op =:= call; Op =:= make_fun ->
+ {I,Count,Acc} = place_retval_copy(I0, Yregs, Copy, Count0, Acc0),
+ {reverse(Acc, [I]),Count};
copy_retval_is([#b_set{}]=Is, false, _Yregs, Copy, Count, Acc) ->
{reverse(Acc, acc_copy(Is, Copy)),Count};
copy_retval_is([#b_set{},#b_set{op=succeeded}]=Is, false, _Yregs, Copy, Count, Acc) ->