diff options
Diffstat (limited to 'lib/compiler/src/beam_dead.erl')
| -rw-r--r-- | lib/compiler/src/beam_dead.erl | 33 |
1 files changed, 30 insertions, 3 deletions
diff --git a/lib/compiler/src/beam_dead.erl b/lib/compiler/src/beam_dead.erl index 0cb5040177..11129c39bc 100644 --- a/lib/compiler/src/beam_dead.erl +++ b/lib/compiler/src/beam_dead.erl @@ -239,10 +239,18 @@ backward([{test,is_eq_exact,Fail,[Dst,{integer,Arity}]}=I| backward([{label,Lbl}=L|Is], D, Acc) -> backward(Is, beam_utils:index_label(Lbl, Acc, D), [L|Acc]); backward([{select,select_val,Reg,{f,Fail0},List0}|Is], D, Acc) -> - List = shortcut_select_list(List0, Reg, D, []), + List1 = shortcut_select_list(List0, Reg, D, []), Fail1 = shortcut_label(Fail0, D), Fail = shortcut_bs_test(Fail1, Is, D), + List = prune_redundant(List1, Fail), case List of + [] -> + Jump = {jump,{f,Fail}}, + backward([Jump|Is], D, Acc); + [V,F] -> + Test = {test,is_eq_exact,{f,Fail},[Reg,V]}, + Jump = {jump,F}, + backward([Jump,Test|Is], D, Acc); [{atom,B1},F,{atom,B2},F] when B1 =:= not B2 -> Test = {test,is_boolean,{f,Fail},[Reg]}, Jump = {jump,F}, @@ -264,14 +272,17 @@ backward([{jump,{f,To}}=J|[{bif,Op,_,Ops,Reg}|Is]=Is0], D, Acc) -> catch throw:not_possible -> backward(Is0, D, [J|Acc]) end; -backward([{test,bs_start_match2,F,_,[R,_],Ctxt}=I|Is], D, +backward([{test,bs_start_match2,F,Live,[R,_]=Args,Ctxt}|Is], D, [{test,bs_match_string,F,[Ctxt,Bs]}, {test,bs_test_tail2,F,[Ctxt,0]}|Acc0]=Acc) -> + {f,To0} = F, + To = shortcut_bs_start_match(To0, R, D), case beam_utils:is_killed(Ctxt, Acc0, D) of true -> - Eq = {test,is_eq_exact,F,[R,{literal,Bs}]}, + Eq = {test,is_eq_exact,{f,To},[R,{literal,Bs}]}, backward(Is, D, [Eq|Acc0]); false -> + I = {test,bs_start_match2,{f,To},Live,Args,Ctxt}, backward(Is, D, [I|Acc]) end; backward([{test,bs_start_match2,{f,To0},Live,[Src|_]=Info,Dst}|Is], D, Acc) -> @@ -307,6 +318,16 @@ backward([{test,Op,{f,To0},Ops0}|Is], D, Acc) -> %% An is_atom test before an is_boolean test (with the %% same failure label) is redundant. backward(Is, D, Acc); + {{test,is_atom,Fail,[R]}, + [{test,is_eq_exact,Fail,[R,{atom,_}]}|_]} -> + %% An is_atom test before a comparison with an atom (with + %% the same failure label) is redundant. + backward(Is, D, Acc); + {{test,is_integer,Fail,[R]}, + [{test,is_eq_exact,Fail,[R,{integer,_}]}|_]} -> + %% An is_integer test before a comparison with an integer + %% (with the same failure label) is redundant. + backward(Is, D, Acc); {{test,_,_,_},_} -> %% Still a test instruction. Done. backward(Is, D, [I|Acc]); @@ -366,6 +387,12 @@ shortcut_label(To0, D) -> shortcut_select_label(To, Reg, Lit, D) -> shortcut_rel_op(To, is_ne_exact, [Reg,Lit], D). +prune_redundant([_,{f,Fail}|T], Fail) -> + prune_redundant(T, Fail); +prune_redundant([V,F|T], Fail) -> + [V,F|prune_redundant(T, Fail)]; +prune_redundant([], _) -> []. + %% Replace a comparison operator with a test instruction and a jump. %% For example, if we have this code: %% |