Merge branch 'bjorn/compiler/ssa'

* bjorn/compiler/ssa:
  Travis CI: Run the SSA linter in the Linux64SmokeTest build
  Remove retired compiler passes
  Introduce a new SSA-based intermediate format
  hipe_beam_to_icode: Correct translation of get_map_elements
  beam_dead: Remove shortcut of binary matching instruction
  beam_bs: Remove optimizations that are easier done on SSA format
  Don't run unsafe compiler passes
  Simplify optimizations by introducing is_nil late
  beam_utils: Make is_tagged_tuple a pure test
  beam_except: Enhance recognition of function_clause exceptions
  beam_validator: Infer the types of copies in a smarter way
  beam_validator: Improve merge of cons and literal list
  beam_validator: Strengthen validation of func_info
  beam_validator: Allow get_tuple_element before dsetelement
  beam_validator: Don't transfer state to labels that can't be reached
  beam_validator: Improve type analysis for tuples
  beam_validator: Be more careful when updating try/catch state
  beam_trim: Handle an empty list of instructions
  v3_core: Number argument variables in ascending order
  Teach binary instructions to use Y registers as destination

OTP-14894

1 files changed, 17 insertions, 2 deletions

diff --git a/lib/compiler/src/beam_a.erl b/lib/compiler/src/beam_a.erl
index 6fd4ace540..266e8f46c8 100644
--- a/lib/compiler/src/beam_a.erl
+++ b/lib/compiler/src/beam_a.erl
@@ -39,8 +39,13 @@ function({function,Name,Arity,CLabel,Is0}) ->
 
 	%% Remove unusued labels for cleanliness and to help
 	%% optimization passes and HiPE.
-	Is = beam_jump:remove_unused_labels(Is1),
-	{function,Name,Arity,CLabel,Is}
+	Is2 = beam_jump:remove_unused_labels(Is1),
+
+        %% Some optimization passes can't handle consecutive labels.
+        %% Coalesce multiple consecutive labels.
+        Is = coalesce_consecutive_labels(Is2, [], []),
+
+        {function,Name,Arity,CLabel,Is}
     catch
         Class:Error:Stack ->
 	    io:fwrite("Function: ~w/~w\n", [Name,Arity]),
@@ -113,6 +118,8 @@ rename_instr({put_map_exact,Fail,S,D,R,L}) ->
     {put_map,Fail,exact,S,D,R,L};
 rename_instr({test,has_map_fields,Fail,Src,{list,List}}) ->
     {test,has_map_fields,Fail,[Src|List]};
+rename_instr({test,is_nil,Fail,[Src]}) ->
+    {test,is_eq_exact,Fail,[Src,nil]};
 rename_instr({select_val=I,Reg,Fail,{list,List}}) ->
     {select,I,Reg,Fail,List};
 rename_instr({select_tuple_arity=I,Reg,Fail,{list,List}}) ->
@@ -120,3 +127,11 @@ rename_instr({select_tuple_arity=I,Reg,Fail,{list,List}}) ->
 rename_instr(send) ->
     {call_ext,2,send};
 rename_instr(I) -> I.
+
+coalesce_consecutive_labels([{label,L}=Lbl,{label,Alias}|Is], Replace, Acc) ->
+    coalesce_consecutive_labels([Lbl|Is], [{Alias,L}|Replace], Acc);
+coalesce_consecutive_labels([I|Is], Replace, Acc) ->
+    coalesce_consecutive_labels(Is, Replace, [I|Acc]);
+coalesce_consecutive_labels([], Replace, Acc) ->
+    D = maps:from_list(Replace),
+    beam_utils:replace_labels(Acc, [], D, fun(L) -> L end).