Refactor removal of unused labels

Since we always want to remove unused labels directly after code
generation (whether we'll run the optimization passes or not),
we can simplify the code by doing it in beam_a.

4 files changed, 15 insertions, 29 deletions

diff --git a/lib/compiler/src/beam_a.erl b/lib/compiler/src/beam_a.erl
index 3d073f63df..496b0aba41 100644
--- a/lib/compiler/src/beam_a.erl
+++ b/lib/compiler/src/beam_a.erl
@@ -28,8 +28,11 @@ module({Mod,Exp,Attr,Fs0,Lc}, _Opt) ->
     Fs = [function(F) || F <- Fs0],
     {ok,{Mod,Exp,Attr,Fs,Lc}}.
 
-function({function,Name,Arity,CLabel,Is}) ->
+function({function,Name,Arity,CLabel,Is0}) ->
     try
+	%% Remove unusued labels for cleanliness and to help
+	%% optimization passes and HiPE.
+	Is = beam_jump:remove_unused_labels(Is0),
 	{function,Name,Arity,CLabel,Is}
     catch
 	Class:Error ->
diff --git a/lib/compiler/src/beam_block.erl b/lib/compiler/src/beam_block.erl
index 109bb1ec0e..f6ebc646bb 100644
--- a/lib/compiler/src/beam_block.erl
+++ b/lib/compiler/src/beam_block.erl
@@ -31,19 +31,16 @@ module({Mod,Exp,Attr,Fs0,Lc0}, _Opt) ->
 
 function({function,Name,Arity,CLabel,Is0}, Lc0) ->
     try
-	%% Extra labels may thwart optimizations.
-	Is1 = beam_jump:remove_unused_labels(Is0),
-
 	%% Collect basic blocks and optimize them.
-	Is2 = blockify(Is1),
-	Is3 = embed_lines(Is2),
-	Is4 = move_allocates(Is3),
-	Is5 = beam_utils:live_opt(Is4),
-	Is6 = opt_blocks(Is5),
-	Is7 = beam_utils:delete_live_annos(Is6),
+	Is1 = blockify(Is0),
+	Is2 = embed_lines(Is1),
+	Is3 = move_allocates(Is2),
+	Is4 = beam_utils:live_opt(Is3),
+	Is5 = opt_blocks(Is4),
+	Is6 = beam_utils:delete_live_annos(Is5),
 
 	%% Optimize bit syntax.
-	{Is,Lc} = bsm_opt(Is7, Lc0),
+	{Is,Lc} = bsm_opt(Is6, Lc0),
 
 	%% Done.
 	{{function,Name,Arity,CLabel,Is},Lc}
diff --git a/lib/compiler/src/beam_jump.erl b/lib/compiler/src/beam_jump.erl
index e7025ea6e8..2b68b3ed20 100644
--- a/lib/compiler/src/beam_jump.erl
+++ b/lib/compiler/src/beam_jump.erl
@@ -20,7 +20,7 @@
 
 -module(beam_jump).
 
--export([module/2,module_labels/1,
+-export([module/2,
 	 is_unreachable_after/1,is_exit_instruction/1,
 	 remove_unused_labels/1,is_label_used_in/2]).
 
@@ -133,13 +133,6 @@ module({Mod,Exp,Attr,Fs0,Lc}, _Opt) ->
     Fs = [function(F) || F <- Fs0],
     {ok,{Mod,Exp,Attr,Fs,Lc}}.
 
-module_labels({Mod,Exp,Attr,Fs,Lc}) ->
-    {Mod,Exp,Attr,[function_labels(F) || F <- Fs],Lc}.
-
-function_labels({function,Name,Arity,CLabel,Asm0}) ->
-    Asm = remove_unused_labels(Asm0),
-    {function,Name,Arity,CLabel,Asm}.    
-
 %% function(Function) -> Function'
 %%  Optimize jumps and branches.
 %%
diff --git a/lib/compiler/src/compile.erl b/lib/compiler/src/compile.erl
index 0346c0441a..df1af36eeb 100644
--- a/lib/compiler/src/compile.erl
+++ b/lib/compiler/src/compile.erl
@@ -660,12 +660,9 @@ asm_passes() ->
 	 {iff,dtrim,{listing,"trim"}},
 	 {pass,beam_flatten}]},
 
-       %% If post optimizations are turned off, we still coalesce
-       %% adjacent labels and remove unused labels to keep the
-       %% HiPE compiler happy.
-       {iff,no_postopt,
-	[?pass(beam_unused_labels),
-	 {pass,beam_clean}]},
+       %% If post optimizations are turned off, we still
+       %% need to do a few clean-ups to code.
+       {iff,no_postopt,[{pass,beam_clean}]},
 
        {pass,beam_z},
        {iff,dopt,{listing,"optimize"}},
@@ -1244,10 +1241,6 @@ random_bytes_1(N, Acc) -> random_bytes_1(N-1, [random:uniform(255)|Acc]).
 save_core_code(St) ->
     {ok,St#compile{core_code=cerl:from_records(St#compile.code)}}.
 
-beam_unused_labels(#compile{code=Code0}=St) ->
-    Code = beam_jump:module_labels(Code0),
-    {ok,St#compile{code=Code}}.
-
 beam_asm(#compile{ifile=File,code=Code0,
 		  abstract_code=Abst,mod_options=Opts0}=St) ->
     Source = filename:absname(File),