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author | John Högberg <[email protected]> | 2019-07-05 11:43:03 +0200 |
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committer | GitHub <[email protected]> | 2019-07-05 11:43:03 +0200 |
commit | 1dc33076f9f633dff1eeb10eef7caaee545e5110 (patch) | |
tree | 2d5ab7cdfec192f98617e15690ad5c70ee2917a8 /lib/compiler | |
parent | c93d582069bf53b8a77ea24111974b3c2a3cd241 (diff) | |
parent | f52918aa4833ceb4f22f89bd436a6c52919b7015 (diff) | |
download | otp-1dc33076f9f633dff1eeb10eef7caaee545e5110.tar.gz otp-1dc33076f9f633dff1eeb10eef7caaee545e5110.tar.bz2 otp-1dc33076f9f633dff1eeb10eef7caaee545e5110.zip |
Merge pull request #2314 from josevalim/jv-set-unused
Collect unused vars instead of used ones
Diffstat (limited to 'lib/compiler')
-rw-r--r-- | lib/compiler/src/beam_ssa.erl | 51 | ||||
-rw-r--r-- | lib/compiler/src/beam_ssa_pre_codegen.erl | 12 |
2 files changed, 29 insertions, 34 deletions
diff --git a/lib/compiler/src/beam_ssa.erl b/lib/compiler/src/beam_ssa.erl index 7a766623b0..c007c7f8d2 100644 --- a/lib/compiler/src/beam_ssa.erl +++ b/lib/compiler/src/beam_ssa.erl @@ -21,7 +21,7 @@ -module(beam_ssa). -export([add_anno/3,get_anno/2,get_anno/3, - clobbers_xregs/1,def/2,def_used/2, + clobbers_xregs/1,def/2,def_unused/3, definitions/1, dominators/1,common_dominators/3, flatmapfold_instrs_rpo/4, @@ -124,7 +124,7 @@ 'put_tuple_element' | 'put_tuple_elements' | 'set_tuple_element'. --import(lists, [foldl/3,keyfind/3,mapfoldl/3,member/2,reverse/1,umerge/1]). +-import(lists, [foldl/3,keyfind/3,mapfoldl/3,member/2,reverse/1]). -spec add_anno(Key, Value, Construct) -> Construct when Key :: atom(), @@ -320,17 +320,18 @@ def(Ls, Blocks) -> Blks = [map_get(L, Blocks) || L <- Top], def_1(Blks, []). --spec def_used(Ls, Blocks) -> {Def,Used} when +-spec def_unused(Ls, Used, Blocks) -> {Def,Unused} when Ls :: [label()], + Used :: ordsets:ordset(var_name()), Blocks :: block_map(), Def :: ordsets:ordset(var_name()), - Used :: ordsets:ordset(var_name()). + Unused :: ordsets:ordset(var_name()). -def_used(Ls, Blocks) -> +def_unused(Ls, Unused, Blocks) -> Top = rpo(Ls, Blocks), Blks = [map_get(L, Blocks) || L <- Top], Preds = cerl_sets:from_list(Top), - def_used_1(Blks, Preds, [], []). + def_unused_1(Blks, Preds, [], Unused). %% dominators(BlockMap) -> {Dominators,Numbering}. %% Calculate the dominator tree, returning a map where each entry @@ -652,34 +653,28 @@ is_commutative('=/=') -> true; is_commutative('/=') -> true; is_commutative(_) -> false. -def_used_1([#b_blk{is=Is,last=Last}|Bs], Preds, Def0, UsedAcc) -> - {Def,Used} = def_used_is(Is, Preds, Def0, used(Last)), - case Used of - [] -> - def_used_1(Bs, Preds, Def, UsedAcc); - [_|_] -> - def_used_1(Bs, Preds, Def, [Used|UsedAcc]) - end; -def_used_1([], _Preds, Def0, UsedAcc) -> - Def = ordsets:from_list(Def0), - Used = umerge(UsedAcc), - {Def,Used}. +def_unused_1([#b_blk{is=Is,last=Last}|Bs], Preds, Def0, Unused0) -> + Unused1 = ordsets:subtract(Unused0, used(Last)), + {Def,Unused} = def_unused_is(Is, Preds, Def0, Unused1), + def_unused_1(Bs, Preds, Def, Unused); +def_unused_1([], _Preds, Def, Unused) -> + {ordsets:from_list(Def), Unused}. -def_used_is([#b_set{op=phi,dst=Dst,args=Args}|Is], - Preds, Def0, Used0) -> +def_unused_is([#b_set{op=phi,dst=Dst,args=Args}|Is], + Preds, Def0, Unused0) -> Def = [Dst|Def0], %% We must be careful to only include variables that will %% be used when arriving from one of the predecessor blocks %% in Preds. - Used1 = [V || {#b_var{}=V,L} <- Args, cerl_sets:is_element(L, Preds)], - Used = ordsets:union(ordsets:from_list(Used1), Used0), - def_used_is(Is, Preds, Def, Used); -def_used_is([#b_set{dst=Dst}=I|Is], Preds, Def0, Used0) -> + Unused1 = [V || {#b_var{}=V,L} <- Args, cerl_sets:is_element(L, Preds)], + Unused = ordsets:subtract(Unused0, ordsets:from_list(Unused1)), + def_unused_is(Is, Preds, Def, Unused); +def_unused_is([#b_set{dst=Dst}=I|Is], Preds, Def0, Unused0) -> Def = [Dst|Def0], - Used = ordsets:union(used(I), Used0), - def_used_is(Is, Preds, Def, Used); -def_used_is([], _Preds, Def, Used) -> - {Def,Used}. + Unused = ordsets:subtract(Unused0, used(I)), + def_unused_is(Is, Preds, Def, Unused); +def_unused_is([], _Preds, Def, Unused) -> + {Def,Unused}. def_1([#b_blk{is=Is}|Bs], Def0) -> Def = def_is(Is, Def0), diff --git a/lib/compiler/src/beam_ssa_pre_codegen.erl b/lib/compiler/src/beam_ssa_pre_codegen.erl index a5fcb91cc0..2c68ab88fa 100644 --- a/lib/compiler/src/beam_ssa_pre_codegen.erl +++ b/lib/compiler/src/beam_ssa_pre_codegen.erl @@ -1449,9 +1449,9 @@ recv_common(_Defs, none, _Blocks) -> %% in the tail position of a function. []; recv_common(Defs, Exit, Blocks) -> - {ExitDefs,ExitUsed} = beam_ssa:def_used([Exit], Blocks), + {ExitDefs,ExitUnused} = beam_ssa:def_unused([Exit], Defs, Blocks), Def = ordsets:subtract(Defs, ExitDefs), - ordsets:intersection(Def, ExitUsed). + ordsets:subtract(Def, ExitUnused). %% recv_fix_common([CommonVar], LoopExit, [RemoveMessageLabel], %% Blocks0, Count0) -> {Blocks,Count}. @@ -1505,9 +1505,9 @@ exit_predecessors([], _Exit, _Blocks) -> []. %% later used within a clause of the receive. fix_receive([L|Ls], Defs, Blocks0, Count0) -> - {RmDefs,Used0} = beam_ssa:def_used([L], Blocks0), + {RmDefs,Unused} = beam_ssa:def_unused([L], Defs, Blocks0), Def = ordsets:subtract(Defs, RmDefs), - Used = ordsets:intersection(Def, Used0), + Used = ordsets:subtract(Def, Unused), {NewVars,Count} = new_vars([Base || #b_var{name=Base} <- Used], Count0), Ren = zip(Used, NewVars), Blocks1 = beam_ssa:rename_vars(Ren, [L], Blocks0), @@ -2133,8 +2133,8 @@ reserve_yregs(#st{frames=Frames}=St0) -> reserve_yregs_1(L, #st{ssa=Blocks0,cnt=Count0,res=Res0}=St) -> Blk = map_get(L, Blocks0), Yregs = beam_ssa:get_anno(yregs, Blk), - {Def,Used} = beam_ssa:def_used([L], Blocks0), - UsedYregs = ordsets:intersection(Yregs, Used), + {Def,Unused} = beam_ssa:def_unused([L], Yregs, Blocks0), + UsedYregs = ordsets:subtract(Yregs, Unused), DefBefore = ordsets:subtract(UsedYregs, Def), {BeforeVars,Blocks,Count} = rename_vars(DefBefore, L, Blocks0, Count0), InsideVars = ordsets:subtract(UsedYregs, DefBefore), |