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-rw-r--r--lib/compiler/src/beam_a.erl29
1 files changed, 27 insertions, 2 deletions
diff --git a/lib/compiler/src/beam_a.erl b/lib/compiler/src/beam_a.erl
index 6fd4ace540..dd2537a699 100644
--- a/lib/compiler/src/beam_a.erl
+++ b/lib/compiler/src/beam_a.erl
@@ -39,14 +39,29 @@ function({function,Name,Arity,CLabel,Is0}) ->
%% Remove unusued labels for cleanliness and to help
%% optimization passes and HiPE.
- Is = beam_jump:remove_unused_labels(Is1),
- {function,Name,Arity,CLabel,Is}
+ Is2 = beam_jump:remove_unused_labels(Is1),
+
+ %% Some optimization passes can't handle consecutive labels.
+ %% Coalesce multiple consecutive labels.
+ Is = coalesce_consecutive_labels(Is2, [], []),
+
+ {function,Name,Arity,CLabel,Is}
catch
Class:Error:Stack ->
io:fwrite("Function: ~w/~w\n", [Name,Arity]),
erlang:raise(Class, Error, Stack)
end.
+rename_instrs([{test,is_eq_exact,_,[Dst,Src]}=Test,
+ {move,Src,Dst}|Is]) ->
+ %% The move instruction is not needed.
+ rename_instrs([Test|Is]);
+rename_instrs([{test,is_eq_exact,_,[Same,Same]}|Is]) ->
+ %% Same literal or same register. Will always succeed.
+ rename_instrs(Is);
+rename_instrs([{loop_rec,{f,Fail},{x,0}},{loop_rec_end,_},{label,Fail}|Is]) ->
+ %% This instruction sequence does nothing.
+ rename_instrs(Is);
rename_instrs([{apply_last,A,N}|Is]) ->
[{apply,A},{deallocate,N},return|rename_instrs(Is)];
rename_instrs([{call_last,A,F,N}|Is]) ->
@@ -113,6 +128,8 @@ rename_instr({put_map_exact,Fail,S,D,R,L}) ->
{put_map,Fail,exact,S,D,R,L};
rename_instr({test,has_map_fields,Fail,Src,{list,List}}) ->
{test,has_map_fields,Fail,[Src|List]};
+rename_instr({test,is_nil,Fail,[Src]}) ->
+ {test,is_eq_exact,Fail,[Src,nil]};
rename_instr({select_val=I,Reg,Fail,{list,List}}) ->
{select,I,Reg,Fail,List};
rename_instr({select_tuple_arity=I,Reg,Fail,{list,List}}) ->
@@ -120,3 +137,11 @@ rename_instr({select_tuple_arity=I,Reg,Fail,{list,List}}) ->
rename_instr(send) ->
{call_ext,2,send};
rename_instr(I) -> I.
+
+coalesce_consecutive_labels([{label,L}=Lbl,{label,Alias}|Is], Replace, Acc) ->
+ coalesce_consecutive_labels([Lbl|Is], [{Alias,L}|Replace], Acc);
+coalesce_consecutive_labels([I|Is], Replace, Acc) ->
+ coalesce_consecutive_labels(Is, Replace, [I|Acc]);
+coalesce_consecutive_labels([], Replace, Acc) ->
+ D = maps:from_list(Replace),
+ beam_utils:replace_labels(Acc, [], D, fun(L) -> L end).