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authorMichał Muskała <[email protected]>2017-08-13 18:24:54 +0200
committerMichał Muskała <[email protected]>2017-08-26 10:20:23 +0200
commit50d8a8b1b0b46d35564ca1c949039ec903cd0937 (patch)
treef48c0b5d8f115caebbca40be004eded355125d14 /lib/compiler/src/beam_peep.erl
parent3d1335be3cde81efff7ba55140d52c2a2d032e8f (diff)
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Enhance optimisations in beam_peep
When cleaning selects, it might happen we're left with only one pair. In such case convert to a regular test + jump.
Diffstat (limited to 'lib/compiler/src/beam_peep.erl')
-rw-r--r--lib/compiler/src/beam_peep.erl28
1 files changed, 25 insertions, 3 deletions
diff --git a/lib/compiler/src/beam_peep.erl b/lib/compiler/src/beam_peep.erl
index 6df5c02334..9436c20b36 100644
--- a/lib/compiler/src/beam_peep.erl
+++ b/lib/compiler/src/beam_peep.erl
@@ -89,15 +89,37 @@ peep([{gc_bif,_,_,_,_,Dst}=I|Is], SeenTests0, Acc) ->
peep([{jump,{f,L}},{label,L}=I|Is], _, Acc) ->
%% Sometimes beam_jump has missed this optimization.
peep(Is, gb_sets:empty(), [I|Acc]);
-peep([{select,Op,R,F,Vls0}|Is], _, Acc) ->
+peep([{select,Op,R,F,Vls0}|Is], SeenTests0, Acc0) ->
case prune_redundant_values(Vls0, F) of
[] ->
%% No values left. Must convert to plain jump.
I = {jump,F},
- peep(Is, gb_sets:empty(), [I|Acc]);
+ peep([I|Is], gb_sets:empty(), Acc0);
+ [{atom,_}=Value,Lbl] when Op =:= select_val ->
+ %% Single value left. Convert to regular test and pop redundant tests.
+ Is1 = [{test,is_eq_exact,F,[R,Value]},{jump,Lbl}|Is],
+ case Acc0 of
+ [{test,is_atom,F,[R]}|Acc] ->
+ peep(Is1, SeenTests0, Acc);
+ _ ->
+ peep(Is1, SeenTests0, Acc0)
+ end;
+ [{integer,_}=Value,Lbl] when Op =:= select_val ->
+ %% Single value left. Convert to regular test and pop redundant tests.
+ Is1 = [{test,is_eq_exact,F,[R,Value]},{jump,Lbl}|Is],
+ case Acc0 of
+ [{test,is_integer,F,[R]}|Acc] ->
+ peep(Is1, SeenTests0, Acc);
+ _ ->
+ peep(Is1, SeenTests0, Acc0)
+ end;
+ [Arity,Lbl] when Op =:= select_tuple_arity ->
+ %% Single value left. Convert to regular test
+ Is1 = [{test,test_arity,F,[R,Arity]},{jump,Lbl}|Is],
+ peep(Is1, SeenTests0, Acc0);
[_|_]=Vls ->
I = {select,Op,R,F,Vls},
- peep(Is, gb_sets:empty(), [I|Acc])
+ peep(Is, gb_sets:empty(), [I|Acc0])
end;
peep([{test,Op,_,Ops}=I|Is], SeenTests0, Acc) ->
case beam_utils:is_pure_test(I) of