Merge branch 'bg/compiler' into dev

* bg/compiler:
  beam_peep: Remove optimization already done by beam_dead
  beam_dead: Combine is_eq_exact instructions into select_val instructions
  Evaluate is_record/3 at compile-time using type information
  Evaluate element/2 at compile-time using type information
  erl_expand_records: Replace is_record() with matching

OTP-8668 bg/compiler

The compiler optimizes record operations better.

3 files changed, 87 insertions, 74 deletions

diff --git a/lib/compiler/src/beam_dead.erl b/lib/compiler/src/beam_dead.erl
index 7b4cd814a2..bb93110176 100644
--- a/lib/compiler/src/beam_dead.erl
+++ b/lib/compiler/src/beam_dead.erl
@@ -1,19 +1,19 @@
 %%
 %% %CopyrightBegin%
-%% 
-%% Copyright Ericsson AB 2002-2009. All Rights Reserved.
-%% 
+%%
+%% Copyright Ericsson AB 2002-2010. All Rights Reserved.
+%%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
 %% compliance with the License. You should have received a copy of the
 %% Erlang Public License along with this software. If not, it can be
 %% retrieved online at http://www.erlang.org/.
-%% 
+%%
 %% Software distributed under the License is distributed on an "AS IS"
 %% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 %% the License for the specific language governing rights and limitations
 %% under the License.
-%% 
+%%
 %% %CopyrightEnd%
 %%
 
@@ -281,12 +281,12 @@ forward([{test,is_eq_exact,_,[Dst,Src]}=I,{move,Src,Dst}|Is], D, Lc, Acc) ->
     forward([I|Is], D, Lc, Acc);
 forward([{test,is_nil,_,[Dst]}=I,{move,nil,Dst}|Is], D, Lc, Acc) ->
     forward([I|Is], D, Lc, Acc);
-forward([{test,is_eq_exact,_,[_,{atom,_}]}=I|Is], D, Lc, [{label,_}|_]=Acc) ->
+forward([{test,is_eq_exact,_,_}=I|Is], D, Lc, Acc) ->
     case Is of
 	[{label,_}|_] -> forward(Is, D, Lc, [I|Acc]);
 	_ -> forward(Is, D, Lc+1, [{label,Lc},I|Acc])
     end;
-forward([{test,is_ne_exact,_,[_,{atom,_}]}=I|Is], D, Lc, [{label,_}|_]=Acc) ->
+forward([{test,is_ne_exact,_,_}=I|Is], D, Lc, Acc) ->
     case Is of
 	[{label,_}|_] -> forward(Is, D, Lc, [I|Acc]);
 	_ -> forward(Is, D, Lc+1, [{label,Lc},I|Acc])
@@ -371,10 +371,10 @@ backward([{test,bs_start_match2,{f,To0},Live,[Src|_]=Info,Dst}|Is], D, Acc) ->
     To = shortcut_bs_start_match(To0, Src, D),
     I = {test,bs_start_match2,{f,To},Live,Info,Dst},
     backward(Is, D, [I|Acc]);
-backward([{test,is_eq_exact=Op,{f,To0},[Reg,{atom,Val}]=Ops}|Is], D, Acc) ->
+backward([{test,is_eq_exact,{f,To0},[Reg,{atom,Val}]=Ops}|Is], D, Acc) ->
     To1 = shortcut_bs_test(To0, Is, D),
     To = shortcut_fail_label(To1, Reg, Val, D),
-    I = {test,Op,{f,To},Ops},
+    I = combine_eqs(To, Ops, D, Acc),
     backward(Is, D, [I|Acc]);
 backward([{test,Op,{f,To0},Ops0}|Is], D, Acc) ->
     To1 = shortcut_bs_test(To0, Is, D),
@@ -394,7 +394,10 @@ backward([{test,Op,{f,To0},Ops0}|Is], D, Acc) ->
 	     _Code ->
 		 To2
 	 end,
-    I = {test,Op,{f,To},Ops0},
+    I = case Op of
+	    is_eq_exact -> combine_eqs(To, Ops0, D, Acc);
+	    _ -> {test,Op,{f,To},Ops0}
+	end,
     backward(Is, D, [I|Acc]);
 backward([{test,Op,{f,To0},Live,Ops0,Dst}|Is], D, Acc) ->
     To1 = shortcut_bs_test(To0, Is, D),
@@ -519,6 +522,41 @@ bif_to_test(Name, Args, Fail) ->
 
 not_possible() -> throw(not_possible).
 
+%% combine_eqs(To, Operands, Acc) -> Instruction.
+%%  Combine two is_eq_exact instructions or (an is_eq_exact
+%%  instruction and a select_val instruction) to a select_val
+%%  instruction if possible.
+%%
+%%  Example:
+%%
+%%      is_eq_exact F1 Reg Lit1		    select_val Reg F2 [ Lit1 L1
+%%   L1:                .                                       Lit2 L2 ]
+%%              	.
+%%                	.	     ==>
+%%                	.
+%%   F1:  is_eq_exact F2 Reg Lit2          F1: is_eq_exact F2 Reg Lit2
+%%   L2:  ....				   L2:
+%%
+combine_eqs(To, [Reg,{Type,_}=Lit1]=Ops, D, [{label,L1}|_])
+  when Type =:= atom; Type =:= integer ->
+    case beam_utils:code_at(To, D) of
+	[{test,is_eq_exact,{f,F2},[Reg,{Type,_}=Lit2]},
+	 {label,L2}|_] when Lit1 =/= Lit2 ->
+	    {select_val,Reg,{f,F2},{list,[Lit1,{f,L1},Lit2,{f,L2}]}};
+	[{select_val,Reg,{f,F2},{list,[{Type,_}|_]=List0}}|_] ->
+	    List = remove_from_list(Lit1, List0),
+	    {select_val,Reg,{f,F2},{list,[Lit1,{f,L1}|List]}};
+	_Is ->
+	    {test,is_eq_exact,{f,To},Ops}
+	end;
+combine_eqs(To, Ops, _D, _Acc) ->
+    {test,is_eq_exact,{f,To},Ops}.
+
+remove_from_list(Lit, [Lit,{f,_}|T]) ->
+    T;
+remove_from_list(Lit, [Val,{f,_}=Fail|T]) ->
+    [Val,Fail|remove_from_list(Lit, T)];
+remove_from_list(_, []) -> [].
 
 %% shortcut_bs_test(TargetLabel, [Instruction], D) -> TargetLabel'
 %%  Try to shortcut the failure label for a bit syntax matching.
diff --git a/lib/compiler/src/beam_peep.erl b/lib/compiler/src/beam_peep.erl
index d03ac4b1f4..f39fc50b95 100644
--- a/lib/compiler/src/beam_peep.erl
+++ b/lib/compiler/src/beam_peep.erl
@@ -1,19 +1,19 @@
 %%
 %% %CopyrightBegin%
-%% 
-%% Copyright Ericsson AB 2008-2009. All Rights Reserved.
-%% 
+%%
+%% Copyright Ericsson AB 2008-2010. All Rights Reserved.
+%%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
 %% compliance with the License. You should have received a copy of the
 %% Erlang Public License along with this software. If not, it can be
 %% retrieved online at http://www.erlang.org/.
-%% 
+%%
 %% Software distributed under the License is distributed on an "AS IS"
 %% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 %% the License for the specific language governing rights and limitations
 %% under the License.
-%% 
+%%
 %% %CopyrightEnd%
 %%
 
@@ -64,22 +64,7 @@ function({function,Name,Arity,CLabel,Is0}) ->
 %%      InEncoding =:= latin1, OutEncoding =:= unicode; 
 %%      InEncoding =:= latin1, OutEncoding =:= utf8 ->
 %%
-%% (2) Code like
-%%
-%%        is_ne_exact Fail Reg Literal1
-%%        is_ne_exact Fail Reg Literal2
-%%        is_ne_exact Fail Reg Literal3
-%%        is_eq_exact UltimateFail Reg Literal4
-%%      Fail: ....
-%%
-%%     can be rewritten to
-%% 
-%%        select_val Reg UltimateFail   [ Literal1 Fail
-%%                                        Literal2 Fail
-%%                                        Literal3 Fail
-%%                                        Literal4 Fail ]
-%%
-%% (3) A select_val/4 instruction that only verifies that
+%% (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:
 %%
@@ -132,7 +117,7 @@ peep([{test,Op,_,Ops}=I|Is], SeenTests0, Acc) ->
 		false ->
 		    %% Remember that we have seen this test.
 		    SeenTests = gb_sets:insert(Test, SeenTests0),
-		    make_select_val(I, Is, SeenTests, Acc)
+		    peep(Is, SeenTests, [I|Acc])
 	    end
     end;
 peep([{select_val,Src,Fail,
@@ -151,33 +136,6 @@ peep([I|Is], _, Acc) ->
     peep(Is, gb_sets:empty(), [I|Acc]);
 peep([], _, Acc) -> reverse(Acc).
 
-make_select_val({test,is_ne_exact,{f,Fail},[Val,Lit]}=I0,
-		Is0, SeenTests, Acc) ->
-    try
-	Type = case Lit of
-		   {atom,_} -> atom;
-		   {integer,_} -> integer;
-		   _ -> throw(impossible)
-	       end,
-	{I,Is} = make_select_val_1(Is0, Fail, Val, Type, [Lit,{f,Fail}]),
-	peep([I|Is], SeenTests, Acc)
-    catch
-	impossible ->
-	    peep(Is0, SeenTests, [I0|Acc])
-    end;
-make_select_val(I, Is, SeenTests, Acc) ->
-    peep(Is, SeenTests, [I|Acc]).
-
-make_select_val_1([{test,is_ne_exact,{f,Fail},[Val,{Type,_}=Lit]}|Is],
-		  Fail, Val, Type, Acc) ->
-      make_select_val_1(Is, Fail, Val, Type, [Lit,{f,Fail}|Acc]);
-make_select_val_1([{test,is_eq_exact,{f,UltimateFail},[Val,{Type,_}=Lit]} |
-		   [{label,Fail}|_]=Is], Fail, Val, Type, Acc) ->
-    Choices = [Lit,{f,Fail}|Acc],
-    I = {select_val,Val,{f,UltimateFail},{list,Choices}},
-    {I,Is};
-make_select_val_1(_Is, _Fail, _Val, _Type, _Acc) -> throw(impossible).
-    
 kill_seen(Dst, Seen0) ->
     gb_sets:from_ordset(kill_seen_1(gb_sets:to_list(Seen0), Dst)).
 
@@ -187,5 +145,3 @@ kill_seen_1([{_,Ops}=Test|T], Dst) ->
 	false -> [Test|kill_seen_1(T, Dst)]
     end;
 kill_seen_1([], _) -> [].
-
-	    
diff --git a/lib/compiler/src/sys_core_fold.erl b/lib/compiler/src/sys_core_fold.erl
index 6202f07479..96015fbe58 100644
--- a/lib/compiler/src/sys_core_fold.erl
+++ b/lib/compiler/src/sys_core_fold.erl
@@ -1038,6 +1038,8 @@ fold_non_lit_args(Call, lists, append, [Arg1,Arg2], _) ->
     eval_append(Call, Arg1, Arg2);
 fold_non_lit_args(Call, erlang, setelement, [Arg1,Arg2,Arg3], _) ->
     eval_setelement(Call, Arg1, Arg2, Arg3);
+fold_non_lit_args(Call, erlang, is_record, [Arg1,Arg2,Arg3], Sub) ->
+    eval_is_record(Call, Arg1, Arg2, Arg3, Sub);
 fold_non_lit_args(Call, erlang, N, Args, Sub) ->
     NumArgs = length(Args),
     case erl_internal:comp_op(N, NumArgs) of
@@ -1194,19 +1196,22 @@ eval_element(Call, #c_literal{val=Pos}, #c_tuple{es=Es}, _Types) when is_integer
 	true ->
 	    eval_failure(Call, badarg)
     end;
-%% eval_element(Call, #c_literal{val=Pos}, #c_var{name=V}, Types)
-%%   when is_integer(Pos) ->
-%%     case orddict:find(V, Types#sub.t) of
-%% 	{ok,#c_tuple{es=Elements}} ->
-%% 	    if
-%% 		1 =< Pos, Pos =< length(Elements) ->
-%% 		    lists:nth(Pos, Elements);
-%% 		true ->
-%% 		    eval_failure(Call, badarg)
-%% 	    end;
-%% 	error ->
-%% 	    Call
-%%     end;
+eval_element(Call, #c_literal{val=Pos}, #c_var{name=V}, Types)
+  when is_integer(Pos) ->
+    case orddict:find(V, Types#sub.t) of
+	{ok,#c_tuple{es=Elements}} ->
+	    if
+		1 =< Pos, Pos =< length(Elements) ->
+		    case lists:nth(Pos, Elements) of
+			#c_alias{var=Alias} -> Alias;
+			Res -> Res
+		    end;
+		true ->
+		    eval_failure(Call, badarg)
+	    end;
+	error ->
+	    Call
+    end;
 eval_element(Call, Pos, Tuple, _Types) ->
     case is_not_integer(Pos) orelse is_not_tuple(Tuple) of
 	true ->
@@ -1215,6 +1220,20 @@ eval_element(Call, Pos, Tuple, _Types) ->
 	    Call
     end.
 
+%% eval_is_record(Call, Var, Tag, Size, Types) -> Val.
+%%  Evaluates is_record/3 using type information.
+%%
+eval_is_record(Call, #c_var{name=V}, #c_literal{val=NeededTag}=Lit,
+	       #c_literal{val=Size}, Types) ->
+    case orddict:find(V, Types#sub.t) of
+	{ok,#c_tuple{es=[#c_literal{val=Tag}|_]=Es}} ->
+	    Lit#c_literal{val=Tag =:= NeededTag andalso
+			  length(Es) =:= Size};
+	_ ->
+	    Call
+    end;
+eval_is_record(Call, _, _, _, _) -> Call.
+
 %% is_not_integer(Core) -> true | false.
 %%  Returns true if Core is definitely not an integer.