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-rw-r--r--lib/compiler/src/beam_dead.erl126
1 files changed, 18 insertions, 108 deletions
diff --git a/lib/compiler/src/beam_dead.erl b/lib/compiler/src/beam_dead.erl
index efad082152..546f0461b9 100644
--- a/lib/compiler/src/beam_dead.erl
+++ b/lib/compiler/src/beam_dead.erl
@@ -85,11 +85,6 @@ move_move_into_block([], Acc) -> reverse(Acc).
%%%
%%% or in:
%%%
-%%% test is_nil SomeLabel Dst
-%%% move nil Dst
-%%%
-%%% or in:
-%%%
%%% select_val Register FailLabel [... Literal => L1...]
%%% .
%%% .
@@ -140,13 +135,8 @@ forward([{test,is_eq_exact,_,[Same,Same]}|Is], D, Lc, Acc) ->
forward([{test,is_eq_exact,_,[Dst,Src]}=I,
{block,[{set,[Dst],[Src],move}|Bl]}|Is], D, Lc, Acc) ->
forward([I,{block,Bl}|Is], D, Lc, Acc);
-forward([{test,is_nil,_,[Dst]}=I,
- {block,[{set,[Dst],[nil],move}|Bl]}|Is], D, Lc, Acc) ->
- forward([I,{block,Bl}|Is], D, Lc, Acc);
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,_,_,_}=I|Is]=Is0, D, Lc, Acc) ->
%% Help the second, backward pass to by inserting labels after
%% relational operators so that they can be skipped if they are
@@ -243,8 +233,7 @@ 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) ->
List1 = shortcut_select_list(List0, Reg, D, []),
- Fail1 = shortcut_label(Fail0, D),
- Fail = shortcut_bs_test(Fail1, Is, D),
+ Fail = shortcut_label(Fail0, D),
List = prune_redundant(List1, Fail),
case List of
[] ->
@@ -314,9 +303,8 @@ backward([{test,bs_start_match2,F,Live,[Src,_]=Args,Ctxt}|Is], D, Acc0) ->
backward(Is, D, [I|Acc0])
end;
backward([{test,Op,{f,To0},Ops0}|Is], D, Acc) ->
- To1 = shortcut_bs_test(To0, Is, D),
- To2 = shortcut_label(To1, D),
- To3 = shortcut_rel_op(To2, Op, Ops0, D),
+ To1 = shortcut_label(To0, D),
+ To2 = shortcut_rel_op(To1, Op, Ops0, D),
%% Try to shortcut a repeated test:
%%
@@ -324,58 +312,44 @@ backward([{test,Op,{f,To0},Ops0}|Is], D, Acc) ->
%% . . . ==> ...
%% Fail1: test Op {f,Fail2} Operands Fail1: test Op {f,Fail2} Operands
%%
- To = case beam_utils:code_at(To3, D) of
- [{test,Op,{f,To4},Ops}|_] ->
+ To = case beam_utils:code_at(To2, D) of
+ [{test,Op,{f,To3},Ops}|_] ->
case equal_ops(Ops0, Ops) of
- true -> To4;
- false -> To3
+ true -> To3;
+ false -> To2
end;
_Code ->
- To3
+ To2
end,
I = case Op of
is_eq_exact -> combine_eqs(To, Ops0, D, Acc);
_ -> {test,Op,{f,To},Ops0}
end,
- case {I,Acc} of
- {{test,is_atom,Fail,Ops0},[{test,is_boolean,Fail,Ops0}|_]} ->
- %% 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,_,_,_},_} ->
+ case I of
+ {test,_,_,_} ->
%% Still a test instruction. Done.
backward(Is, D, [I|Acc]);
- {_,_} ->
+ _ ->
%% Rewritten to a select_val. Rescan.
backward([I|Is], D, Acc)
end;
backward([{test,Op,{f,To0},Live,Ops0,Dst}|Is], D, Acc) ->
- To1 = shortcut_bs_test(To0, Is, D),
- To2 = shortcut_label(To1, D),
+ To1 = shortcut_label(To0, D),
+
%% Try to shortcut a repeated test:
%%
%% test Op {f,Fail1} _ Ops _ test Op {f,Fail2} _ Ops _
%% . . . ==> ...
%% Fail1: test Op {f,Fail2} _ Ops _ Fail1: test Op {f,Fail2} _ Ops _
%%
- To = case beam_utils:code_at(To2, D) of
- [{test,Op,{f,To3},_,Ops,_}|_] ->
+ To = case beam_utils:code_at(To1, D) of
+ [{test,Op,{f,To2},_,Ops,_}|_] ->
case equal_ops(Ops0, Ops) of
- true -> To3;
- false -> To2
+ true -> To2;
+ false -> To1
end;
_Code ->
- To2
+ To1
end,
I = {test,Op,{f,To},Live,Ops0,Dst},
backward(Is, D, [I|Acc]);
@@ -548,68 +522,6 @@ test_bs_literal_1(Ctxt, Is, D, Literal) ->
false -> not_killed
end.
-%% shortcut_bs_test(TargetLabel, ReversedInstructions, D) -> TargetLabel'
-%% Try to shortcut the failure label for bit syntax matching.
-
-shortcut_bs_test(To, Is, D) ->
- shortcut_bs_test_1(beam_utils:code_at(To, D), Is, To, D).
-
-shortcut_bs_test_1([{bs_restore2,Reg,SavePoint},
- {label,_},
- {test,bs_test_tail2,{f,To},[_,TailBits]}|_],
- PrevIs, To0, D) ->
- case count_bits_matched(PrevIs, {Reg,SavePoint}, 0) of
- Bits when Bits > TailBits ->
- %% This instruction will fail. We know because a restore has been
- %% done from the previous point SavePoint in the binary, and we
- %% also know that the binary contains at least Bits bits from
- %% SavePoint.
- %%
- %% Since we will skip a bs_restore2 if we shortcut to label To,
- %% we must now make sure that code at To does not depend on
- %% the position in the context in any way.
- case shortcut_bs_pos_used(To, Reg, D) of
- false -> To;
- true -> To0
- end;
- _Bits ->
- To0
- end;
-shortcut_bs_test_1([_|_], _, To, _) -> To.
-
-%% counts_bits_matched(ReversedInstructions, SavePoint, Bits) -> Bits'
-%% Given a reversed instruction stream, determine the minimum number
-%% of bits that will be matched by bit syntax instructions up to the
-%% given save point.
-
-count_bits_matched([{test,bs_get_utf8,{f,_},_,_,_}|Is], SavePoint, Bits) ->
- count_bits_matched(Is, SavePoint, Bits+8);
-count_bits_matched([{test,bs_get_utf16,{f,_},_,_,_}|Is], SavePoint, Bits) ->
- count_bits_matched(Is, SavePoint, Bits+16);
-count_bits_matched([{test,bs_get_utf32,{f,_},_,_,_}|Is], SavePoint, Bits) ->
- count_bits_matched(Is, SavePoint, Bits+32);
-count_bits_matched([{test,_,_,_,[_,Sz,U,{field_flags,_}],_}|Is], SavePoint, Bits) ->
- case Sz of
- {integer,N} -> count_bits_matched(Is, SavePoint, Bits+N*U);
- _ -> count_bits_matched(Is, SavePoint, Bits)
- end;
-count_bits_matched([{test,bs_match_string,_,[_,Bs]}|Is], SavePoint, Bits) ->
- count_bits_matched(Is, SavePoint, Bits+bit_size(Bs));
-count_bits_matched([{test,_,_,_}|Is], SavePoint, Bits) ->
- count_bits_matched(Is, SavePoint, Bits);
-count_bits_matched([{bs_save2,Reg,SavePoint}|_], {Reg,SavePoint}, Bits) ->
- %% The save point we are looking for - we are done.
- Bits;
-count_bits_matched([_|_], _, Bits) -> Bits.
-
-shortcut_bs_pos_used(To, Reg, D) ->
- shortcut_bs_pos_used_1(beam_utils:code_at(To, D), Reg, D).
-
-shortcut_bs_pos_used_1([{bs_context_to_binary,Reg}|_], Reg, _) ->
- false;
-shortcut_bs_pos_used_1(Is, Reg, D) ->
- not beam_utils:is_killed(Reg, Is, D).
-
%% shortcut_bs_start_match(TargetLabel, Reg) -> TargetLabel
%% A failing bs_start_match2 instruction means that the source (Reg)
%% cannot be a binary. That means that it is safe to skip
@@ -900,8 +812,6 @@ normalize_op({test,is_eq_exact,{f,Fail},Ops}) ->
normalize_op_1('=:=', Ops, Fail);
normalize_op({test,is_ne_exact,{f,Fail},Ops}) ->
normalize_op_1('=/=', Ops, Fail);
-normalize_op({test,is_nil,{f,Fail},[R]}) ->
- normalize_op_1('=:=', [R,nil], Fail);
normalize_op({test,Op,{f,Fail},[R]}) ->
case erl_internal:new_type_test(Op, 1) of
true -> {{Op,R},Fail};
generated by cgit v1.2.3 (git 2.25.1) at 2024-08-04 11:59:44 +0000