From f63b503f9c7ea4d5824899dc5b287075e261e6a8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Mon, 10 Aug 2015 14:27:50 +0200
Subject: Move rewriting of select_val to is_boolean from beam_peep to
 beam_dead

We can rewrite more instances of select_val to is_boolean because
it is not necessary that a particular label follows the select_val.
---
 lib/compiler/src/beam_peep.erl | 28 ----------------------------
 1 file changed, 28 deletions(-)

(limited to 'lib/compiler/src/beam_peep.erl')

diff --git a/lib/compiler/src/beam_peep.erl b/lib/compiler/src/beam_peep.erl
index 17fd2e502a..75be86b83f 100644
--- a/lib/compiler/src/beam_peep.erl
+++ b/lib/compiler/src/beam_peep.erl
@@ -65,18 +65,6 @@ function({function,Name,Arity,CLabel,Is0}) ->
 %%      InEncoding =:= latin1, OutEncoding =:= unicode; 
 %%      InEncoding =:= latin1, OutEncoding =:= utf8 ->
 %%
-%% (2) A select_val/4 instruction that only verifies that
-%%     its argument is either 'true' or 'false' can be
-%%     be replaced with an is_boolean/2 instruction. That is:
-%%
-%%          select_val Reg Fail   [ true Next false Next ]
-%%        Next: ...
-%%         
-%%     can be rewritten to
-%%
-%%          is_boolean Fail Reg
-%%        Next: ...
-%%
 
 peep(Is) ->
     peep(Is, gb_sets:empty(), []).
@@ -95,12 +83,6 @@ peep([{gc_bif,_,_,_,_,Dst}=I|Is], SeenTests0, Acc) ->
     %% Kill all remembered tests that depend on the destination register.
     SeenTests = kill_seen(Dst, SeenTests0),
     peep(Is, SeenTests, [I|Acc]);
-peep([{test,is_boolean,{f,Fail},Ops}|_]=Is, SeenTests,
-     [{test,is_atom,{f,Fail},Ops}|Acc]) ->
-    %% The previous is_atom/2 test (with the same failure label) is redundant.
-    %% (If is_boolean(Src) is true, is_atom(Src) is also true, so it is
-    %% OK to still remember that we have seen is_atom/1.)
-    peep(Is, SeenTests, Acc);
 peep([{test,Op,_,Ops}=I|Is], SeenTests0, Acc) ->
     case beam_utils:is_pure_test(I) of
 	false ->
@@ -121,16 +103,6 @@ peep([{test,Op,_,Ops}=I|Is], SeenTests0, Acc) ->
 		    peep(Is, SeenTests, [I|Acc])
 	    end
     end;
-peep([{select,select_val,Src,Fail,
-       [{atom,false},{f,L},{atom,true},{f,L}]}|
-      [{label,L}|_]=Is], SeenTests, Acc) ->
-    I = {test,is_boolean,Fail,[Src]},
-    peep([I|Is], SeenTests, Acc);
-peep([{select,select_val,Src,Fail,
-       [{atom,true},{f,L},{atom,false},{f,L}]}|
-      [{label,L}|_]=Is], SeenTests, Acc) ->
-    I = {test,is_boolean,Fail,[Src]},
-    peep([I|Is], SeenTests, Acc);
 peep([I|Is], _, Acc) ->
     %% An unknown instruction. Throw away all information we
     %% have collected about test instructions.
-- 
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