aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorBjörn Gustavsson <[email protected]>2019-01-16 19:31:22 +0100
committerBjörn Gustavsson <[email protected]>2019-01-18 05:45:59 +0100
commit9814a205a2cf9e1024261e2eee80e460e78600d0 (patch)
treea97da08a59b97226280e88fbb0e944cd44917c4b
parent9c852215c79ed6ec42c223463d4b5a0c221b4bf0 (diff)
downloadotp-9814a205a2cf9e1024261e2eee80e460e78600d0.tar.gz
otp-9814a205a2cf9e1024261e2eee80e460e78600d0.tar.bz2
otp-9814a205a2cf9e1024261e2eee80e460e78600d0.zip
beam_ssa_opt: Run the type optimization pass twice
The code will be significantly improved by running the type optimization pass twice. The ssa_opt_misc pass can be eliminated because everything it does is also done by the type optimization pass.
-rw-r--r--lib/compiler/src/beam_ssa_opt.erl102
1 files changed, 9 insertions, 93 deletions
diff --git a/lib/compiler/src/beam_ssa_opt.erl b/lib/compiler/src/beam_ssa_opt.erl
index e23e62b5ad..df40c918b2 100644
--- a/lib/compiler/src/beam_ssa_opt.erl
+++ b/lib/compiler/src/beam_ssa_opt.erl
@@ -22,7 +22,7 @@
-export([module/2]).
-include("beam_ssa.hrl").
--import(lists, [all/2,append/1,foldl/3,keyfind/3,member/2,
+-import(lists, [append/1,foldl/3,keyfind/3,member/2,
reverse/1,reverse/2,
splitwith/2,takewhile/2,unzip/1]).
@@ -55,9 +55,13 @@ passes(Opts0) ->
?PASS(ssa_opt_record),
%% Run ssa_opt_cse twice, because it will help ssa_opt_dead,
- %% and ssa_opt_dead will help ssa_opt_cse. Run ssa_opt_live
- %% twice, because it will help ssa_opt_dead and ssa_opt_dead
- %% will help ssa_opt_live.
+ %% and ssa_opt_dead will help ssa_opt_cse.
+ %%
+ %% Run ssa_opt_live twice, because it will help ssa_opt_dead
+ %% and ssa_opt_dead will help ssa_opt_live.
+ %%
+ %% Run beam_ssa_type twice, because there will be more
+ %% opportunities for optimizations after running beam_ssa_dead.
?PASS(ssa_opt_cse),
?PASS(ssa_opt_type),
?PASS(ssa_opt_live),
@@ -65,12 +69,12 @@ passes(Opts0) ->
?PASS(ssa_opt_dead),
?PASS(ssa_opt_cse), %Second time.
?PASS(ssa_opt_float),
+ ?PASS(ssa_opt_type), %Second time.
?PASS(ssa_opt_live), %Second time.
?PASS(ssa_opt_bsm),
?PASS(ssa_opt_bsm_units),
?PASS(ssa_opt_bsm_shortcut),
- ?PASS(ssa_opt_misc),
?PASS(ssa_opt_tuple_size),
?PASS(ssa_opt_sw),
?PASS(ssa_opt_blockify),
@@ -1346,94 +1350,6 @@ opt_bs_put_split_int_1(Int, L, R) ->
end.
%%%
-%%% Miscellanous optimizations in execution order.
-%%%
-
-ssa_opt_misc(#st{ssa=Linear}=St) ->
- St#st{ssa=misc_opt(Linear, #{})}.
-
-misc_opt([{L,#b_blk{is=Is0,last=Last0}=Blk0}|Bs], Sub0) ->
- {Is,Sub} = misc_opt_is(Is0, Sub0, []),
- Last = sub(Last0, Sub),
- Blk = Blk0#b_blk{is=Is,last=Last},
- [{L,Blk}|misc_opt(Bs, Sub)];
-misc_opt([], _) -> [].
-
-misc_opt_is([#b_set{op=phi}=I0|Is], Sub0, Acc) ->
- #b_set{dst=Dst,args=Args} = I = sub(I0, Sub0),
- case all_same(Args) of
- true ->
- %% Eliminate the phi node if there is just one source
- %% value or if the values are identical.
- [{Val,_}|_] = Args,
- Sub = Sub0#{Dst=>Val},
- misc_opt_is(Is, Sub, Acc);
- false ->
- misc_opt_is(Is, Sub0, [I|Acc])
- end;
-misc_opt_is([#b_set{op={bif,'and'}}=I0], Sub, Acc) ->
- #b_set{dst=Dst,args=Args} = I = sub(I0, Sub),
- case eval_and(Args) of
- error ->
- misc_opt_is([], Sub, [I|Acc]);
- Val ->
- misc_opt_is([], Sub#{Dst=>Val}, Acc)
- end;
-misc_opt_is([#b_set{op={bif,'or'}}=I0], Sub, Acc) ->
- #b_set{dst=Dst,args=Args} = I = sub(I0, Sub),
- case eval_or(Args) of
- error ->
- misc_opt_is([], Sub, [I|Acc]);
- Val ->
- misc_opt_is([], Sub#{Dst=>Val}, Acc)
- end;
-misc_opt_is([#b_set{}=I0|Is], Sub, Acc) ->
- #b_set{op=Op,dst=Dst,args=Args} = I = sub(I0, Sub),
- case make_literal(Op, Args) of
- #b_literal{}=Literal ->
- misc_opt_is(Is, Sub#{Dst=>Literal}, Acc);
- error ->
- misc_opt_is(Is, Sub, [I|Acc])
- end;
-misc_opt_is([], Sub, Acc) ->
- {reverse(Acc),Sub}.
-
-all_same([{H,_}|T]) ->
- all(fun({E,_}) -> E =:= H end, T).
-
-make_literal(put_tuple, Args) ->
- case make_literal_list(Args, []) of
- error ->
- error;
- List ->
- #b_literal{val=list_to_tuple(List)}
- end;
-make_literal(put_list, [#b_literal{val=H},#b_literal{val=T}]) ->
- #b_literal{val=[H|T]};
-make_literal(_, _) -> error.
-
-make_literal_list([#b_literal{val=H}|T], Acc) ->
- make_literal_list(T, [H|Acc]);
-make_literal_list([_|_], _) ->
- error;
-make_literal_list([], Acc) ->
- reverse(Acc).
-
-eval_and(Args) ->
- case Args of
- [_,#b_literal{val=false}=Res] -> Res;
- [Res,#b_literal{val=true}] -> Res;
- [_,_] -> error
- end.
-
-eval_or(Args) ->
- case Args of
- [Res,#b_literal{val=false}] -> Res;
- [_,#b_literal{val=true}=Res] -> Res;
- [_,_] -> error
- end.
-
-%%%
%%% Optimize expressions such as "tuple_size(Var) =:= 2".
%%%
%%% Consider this code: