diff options
Diffstat (limited to 'lib/compiler/src/beam_dead.erl')
| -rw-r--r-- | lib/compiler/src/beam_dead.erl | 48 |
1 files changed, 43 insertions, 5 deletions
diff --git a/lib/compiler/src/beam_dead.erl b/lib/compiler/src/beam_dead.erl index 7b4cd814a2..e690d1b96b 100644 --- a/lib/compiler/src/beam_dead.erl +++ b/lib/compiler/src/beam_dead.erl @@ -281,12 +281,12 @@ forward([{test,is_eq_exact,_,[Dst,Src]}=I,{move,Src,Dst}|Is], D, Lc, Acc) -> forward([I|Is], D, Lc, Acc); forward([{test,is_nil,_,[Dst]}=I,{move,nil,Dst}|Is], D, Lc, Acc) -> forward([I|Is], D, Lc, Acc); -forward([{test,is_eq_exact,_,[_,{atom,_}]}=I|Is], D, Lc, [{label,_}|_]=Acc) -> +forward([{test,is_eq_exact,_,_}=I|Is], D, Lc, Acc) -> case Is of [{label,_}|_] -> forward(Is, D, Lc, [I|Acc]); _ -> forward(Is, D, Lc+1, [{label,Lc},I|Acc]) end; -forward([{test,is_ne_exact,_,[_,{atom,_}]}=I|Is], D, Lc, [{label,_}|_]=Acc) -> +forward([{test,is_ne_exact,_,_}=I|Is], D, Lc, Acc) -> case Is of [{label,_}|_] -> forward(Is, D, Lc, [I|Acc]); _ -> forward(Is, D, Lc+1, [{label,Lc},I|Acc]) @@ -371,10 +371,10 @@ backward([{test,bs_start_match2,{f,To0},Live,[Src|_]=Info,Dst}|Is], D, Acc) -> To = shortcut_bs_start_match(To0, Src, D), I = {test,bs_start_match2,{f,To},Live,Info,Dst}, backward(Is, D, [I|Acc]); -backward([{test,is_eq_exact=Op,{f,To0},[Reg,{atom,Val}]=Ops}|Is], D, Acc) -> +backward([{test,is_eq_exact,{f,To0},[Reg,{atom,Val}]=Ops}|Is], D, Acc) -> To1 = shortcut_bs_test(To0, Is, D), To = shortcut_fail_label(To1, Reg, Val, D), - I = {test,Op,{f,To},Ops}, + I = combine_eqs(To, Ops, D, Acc), backward(Is, D, [I|Acc]); backward([{test,Op,{f,To0},Ops0}|Is], D, Acc) -> To1 = shortcut_bs_test(To0, Is, D), @@ -394,7 +394,10 @@ backward([{test,Op,{f,To0},Ops0}|Is], D, Acc) -> _Code -> To2 end, - I = {test,Op,{f,To},Ops0}, + I = case Op of + is_eq_exact -> combine_eqs(To, Ops0, D, Acc); + _ -> {test,Op,{f,To},Ops0} + end, backward(Is, D, [I|Acc]); backward([{test,Op,{f,To0},Live,Ops0,Dst}|Is], D, Acc) -> To1 = shortcut_bs_test(To0, Is, D), @@ -519,6 +522,41 @@ bif_to_test(Name, Args, Fail) -> not_possible() -> throw(not_possible). +%% combine_eqs(To, Operands, Acc) -> Instruction. +%% Combine two is_eq_exact instructions or (an is_eq_exact +%% instruction and a select_val instruction) to a select_val +%% instruction if possible. +%% +%% Example: +%% +%% is_eq_exact F1 Reg Lit1 select_val Reg F2 [ Lit1 L1 +%% L1: . Lit2 L2 ] +%% . +%% . ==> +%% . +%% F1: is_eq_exact F2 Reg Lit2 F1: is_eq_exact F2 Reg Lit2 +%% L2: .... L2: +%% +combine_eqs(To, [Reg,{Type,_}=Lit1]=Ops, D, [{label,L1}|_]) + when Type =:= atom; Type =:= integer -> + case beam_utils:code_at(To, D) of + [{test,is_eq_exact,{f,F2},[Reg,{Type,_}=Lit2]}, + {label,L2}|_] when Lit1 =/= Lit2 -> + {select_val,Reg,{f,F2},{list,[Lit1,{f,L1},Lit2,{f,L2}]}}; + [{select_val,Reg,{f,F2},{list,[{Type,_}|_]=List0}}|_] -> + List = remove_from_list(Lit1, List0), + {select_val,Reg,{f,F2},{list,[Lit1,{f,L1}|List]}}; + _Is -> + {test,is_eq_exact,{f,To},Ops} + end; +combine_eqs(To, Ops, _D, _Acc) -> + {test,is_eq_exact,{f,To},Ops}. + +remove_from_list(Lit, [Lit,{f,_}|T]) -> + T; +remove_from_list(Lit, [Val,{f,_}=Fail|T]) -> + [Val,Fail|remove_from_list(Lit, T)]; +remove_from_list(_, []) -> []. %% shortcut_bs_test(TargetLabel, [Instruction], D) -> TargetLabel' %% Try to shortcut the failure label for a bit syntax matching. |