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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
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.
-rw-r--r--lib/compiler/src/beam_peep.erl28
-rw-r--r--lib/compiler/test/match_SUITE.erl64
2 files changed, 87 insertions, 5 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
diff --git a/lib/compiler/test/match_SUITE.erl b/lib/compiler/test/match_SUITE.erl
index 52b2da05f7..c31695be24 100644
--- a/lib/compiler/test/match_SUITE.erl
+++ b/lib/compiler/test/match_SUITE.erl
@@ -23,7 +23,7 @@
init_per_group/2,end_per_group/2,
pmatch/1,mixed/1,aliases/1,non_matching_aliases/1,
match_in_call/1,untuplify/1,shortcut_boolean/1,letify_guard/1,
- selectify/1,underscore/1,match_map/1,map_vars_used/1,
+ selectify/1,deselectify/1,underscore/1,match_map/1,map_vars_used/1,
coverage/1,grab_bag/1,literal_binary/1]).
-include_lib("common_test/include/ct.hrl").
@@ -38,7 +38,7 @@ groups() ->
[{p,[parallel],
[pmatch,mixed,aliases,non_matching_aliases,
match_in_call,untuplify,
- shortcut_boolean,letify_guard,selectify,
+ shortcut_boolean,letify_guard,selectify,deselectify,
underscore,match_map,map_vars_used,coverage,
grab_bag,literal_binary]}].
@@ -466,6 +466,66 @@ sel_same_value2(V) when V =:= 42; V =:= 43 ->
sel_same_value2(_) ->
error.
+%% Test deconstruction of select_val instructions in beam_peep into
+%% regular tests with just one possible value left. Hitting proper cases
+%% in beam_peep relies on unification of labels by beam_jump.
+
+deselectify(Config) when is_list(Config) ->
+ one_or_other = desel_tuple_arity({1}),
+ two = desel_tuple_arity({1,1}),
+ one_or_other = desel_tuple_arity({1,1,1}),
+
+ one_or_other = dsel_integer(1),
+ two = dsel_integer(2),
+ one_or_other = dsel_integer(3),
+
+ one_or_other = dsel_integer_typecheck(1),
+ two = dsel_integer_typecheck(2),
+ one_or_other = dsel_integer_typecheck(3),
+
+ one_or_other = dsel_atom(one),
+ two = dsel_atom(two),
+ one_or_other = dsel_atom(three),
+
+ one_or_other = dsel_atom_typecheck(one),
+ two = dsel_atom_typecheck(two),
+ one_or_other = dsel_atom_typecheck(three).
+
+desel_tuple_arity(Tuple) when is_tuple(Tuple) ->
+ case Tuple of
+ {_} -> one_or_other;
+ {_,_} -> two;
+ _ -> one_or_other
+ end.
+
+dsel_integer(Val) ->
+ case Val of
+ 1 -> one_or_other;
+ 2 -> two;
+ _ -> one_or_other
+ end.
+
+dsel_integer_typecheck(Val) when is_integer(Val) ->
+ case Val of
+ 1 -> one_or_other;
+ 2 -> two;
+ _ -> one_or_other
+ end.
+
+dsel_atom(Val) ->
+ case Val of
+ one -> one_or_other;
+ two -> two;
+ _ -> one_or_other
+ end.
+
+dsel_atom_typecheck(Val) when is_atom(Val) ->
+ case Val of
+ one -> one_or_other;
+ two -> two;
+ _ -> one_or_other
+ end.
+
underscore(Config) when is_list(Config) ->
case Config of
[] ->