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authorBjörn Gustavsson <[email protected]>2018-08-30 06:55:37 +0200
committerBjörn Gustavsson <[email protected]>2018-09-12 14:19:05 +0200
commit8e4f23224a90d35683dbd45007682c861c4eb354 (patch)
tree4e1b6246c1f1389d716a7df2882481250cb8a20c
parent71182c868e97dac0833c710c033fde871eb3a8f0 (diff)
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beam_peep: Add is_boolean optimization of select_val
A select_val instruction that test whether a register is a boolean like this: {select_val,Reg,{f,Fail},{list,[{atom,true},Lbl,{atom,false},Lbl]}}. can be replaced with an is_boolean test: {test,is_boolean,{f,Fail},[Reg]}. {jump,{f,Lbl}}. This optimization is currently done in beam_dead. However, if done in the beam_peep, it can catch more opportunities to do the optimization, because after having run beam_jump, labels that were different have been coalesced.
-rw-r--r--lib/compiler/src/beam_peep.erl4
1 files changed, 4 insertions, 0 deletions
diff --git a/lib/compiler/src/beam_peep.erl b/lib/compiler/src/beam_peep.erl
index 74da6aa704..2323a439e9 100644
--- a/lib/compiler/src/beam_peep.erl
+++ b/lib/compiler/src/beam_peep.erl
@@ -112,6 +112,10 @@ peep([{select,Op,R,F,Vls0}|Is], SeenTests0, Acc0) ->
%% Single value left. Convert to regular test
Is1 = [{test,test_arity,F,[R,Arity]},{jump,Lbl}|Is],
peep(Is1, SeenTests0, Acc0);
+ [{atom,B1},Lbl,{atom,B2},Lbl] when B1 =:= not B2 ->
+ %% Replace with is_boolean test.
+ Is1 = [{test,is_boolean,F,[R]},{jump,Lbl}|Is],
+ peep(Is1, SeenTests0, Acc0);
[_|_]=Vls ->
I = {select,Op,R,F,Vls},
peep(Is, gb_sets:empty(), [I|Acc0])