Merge branch 'master' into sverk/master/halt-INT_MIN

1 files changed, 16 insertions, 28 deletions

diff --git a/lib/compiler/src/beam_peep.erl b/lib/compiler/src/beam_peep.erl
index 17fd2e502a..0c1abfe6a0 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 +83,16 @@ 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([{select,Op,R,F,Vls0}|Is], _, Acc) ->
+    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]);
+	[_|_]=Vls ->
+	    I = {select,Op,R,F,Vls},
+	    peep(Is, gb_sets:empty(), [I|Acc])
+    end;
 peep([{test,Op,_,Ops}=I|Is], SeenTests0, Acc) ->
     case beam_utils:is_pure_test(I) of
 	false ->
@@ -121,16 +113,6 @@ 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.
@@ -155,3 +137,9 @@ kill_seen_1([{_,Ops}=Test|T], Dst) ->
 	false -> [Test|kill_seen_1(T, Dst)]
     end;
 kill_seen_1([], _) -> [].
+
+prune_redundant_values([_Val,F|Vls], F) ->
+    prune_redundant_values(Vls, F);
+prune_redundant_values([Val,Lbl|Vls], F) ->
+    [Val,Lbl|prune_redundant_values(Vls, F)];
+prune_redundant_values([], _) -> [].