From 7fed1e036b0c70aaa1e738a403379bab96745e63 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Micha=C5=82=20Muska=C5=82a?= Date: Wed, 6 Jun 2018 19:10:05 +0200 Subject: Optimise beam_jump This is an alternative to #1832. The optimisation relies on special-casing the common pattern of "renaming" a label by direct jump to another label. The change makes beam_jump recognise couple more opportunities for optimisation. The optimisation additionally avoids superfluous list concatenations by only flattening the accumulator at the very end. --- lib/compiler/src/beam_jump.erl | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) (limited to 'lib/compiler/src/beam_jump.erl') diff --git a/lib/compiler/src/beam_jump.erl b/lib/compiler/src/beam_jump.erl index c33de217bd..19c26d4ef9 100644 --- a/lib/compiler/src/beam_jump.erl +++ b/lib/compiler/src/beam_jump.erl @@ -164,17 +164,19 @@ share(Is0) -> share_1([{label,L}=Lbl|Is], Dict0, Lbls0, [_|_]=Seq, Acc) -> case maps:find(Seq, Dict0) of - error -> - Dict = maps:put(Seq, L, Dict0), - share_1(Is, Dict, Lbls0, [], [Lbl|Seq ++ Acc]); - {ok,Label} -> + error -> + Dict = maps:put(Seq, L, Dict0), + share_1(Is, Dict, Lbls0, [], [[Lbl|Seq]|Acc]); + {ok,Label} -> Lbls = maps:put(L, Label, Lbls0), - share_1(Is, Dict0, Lbls, [], [Lbl,{jump,{f,Label}}|Acc]) + share_1(Is, Dict0, Lbls, [], [[Lbl,{jump,{f,Label}}]|Acc]) end; -share_1([{func_info,_,_,_}|_]=Is, _, Lbls, [], Acc) when Lbls =/= #{} -> - beam_utils:replace_labels(Acc, Is, Lbls, fun(Old) -> Old end); +share_1([{func_info,_,_,_}|_]=Is0, _, Lbls, [], Acc0) when Lbls =/= #{} -> + lists:foldl(fun(Is, Acc) -> + beam_utils:replace_labels(Is, Acc, Lbls, fun(Old) -> Old end) + end, Is0, Acc0); share_1([{func_info,_,_,_}|_]=Is, _, Lbls, [], Acc) when Lbls =:= #{} -> - reverse(Acc, Is); + lists:foldl(fun lists:reverse/2, Is, Acc); share_1([{'catch',_,_}=I|Is], Dict0, Lbls0, Seq, Acc) -> {Dict,Lbls} = clean_non_sharable(Dict0, Lbls0), share_1(Is, Dict, Lbls, [I|Seq], Acc); @@ -187,6 +189,9 @@ share_1([{try_case,_}=I|Is], Dict0, Lbls0, Seq, Acc) -> share_1([{catch_end,_}=I|Is], Dict0, Lbls0, Seq, Acc) -> {Dict,Lbls} = clean_non_sharable(Dict0, Lbls0), share_1(Is, Dict, Lbls, [I|Seq], Acc); +share_1([{jump,{f,To}}=I,{label,L}=Lbl|Is], Dict0, Lbls0, _Seq, Acc) -> + Lbls = maps:put(L, To, Lbls0), + share_1(Is, Dict0, Lbls, [], [[Lbl,I]|Acc]); share_1([I|Is], Dict, Lbls, Seq, Acc) -> case is_unreachable_after(I) of false -> -- cgit v1.2.3