Merge pull request #2167 from bjorng/bjorn/tune-beam

Tune BEAM instructions for the new compiler (part 1)

1 files changed, 71 insertions, 21 deletions

diff --git a/lib/compiler/src/beam_ssa_opt.erl b/lib/compiler/src/beam_ssa_opt.erl
index 6e548dd529..bcf55f3fda 100644
--- a/lib/compiler/src/beam_ssa_opt.erl
+++ b/lib/compiler/src/beam_ssa_opt.erl
@@ -175,6 +175,7 @@ epilogue_passes(Opts) ->
           ?PASS(ssa_opt_blockify),
           ?PASS(ssa_opt_sink),
           ?PASS(ssa_opt_merge_blocks),
+          ?PASS(ssa_opt_get_tuple_element),
           ?PASS(ssa_opt_trim_unreachable)],
     passes_1(Ps, Opts).
 
@@ -682,6 +683,14 @@ record_opt_is([#b_set{op={bif,is_tuple},dst=Bool,args=[Tuple]}=Set],
         no ->
             [Set]
     end;
+record_opt_is([I|Is]=Is0, #b_br{bool=Bool}=Last, Blocks) ->
+    case is_tagged_tuple_1(Is0, Last, Blocks) of
+        {yes,_Fail,Tuple,Arity,Tag} ->
+            Args = [Tuple,Arity,Tag],
+            [I#b_set{op=is_tagged_tuple,dst=Bool,args=Args}];
+        no ->
+            [I|record_opt_is(Is, Last, Blocks)]
+    end;
 record_opt_is([I|Is], Last, Blocks) ->
     [I|record_opt_is(Is, Last, Blocks)];
 record_opt_is([], _Last, _Blocks) -> [].
@@ -689,29 +698,30 @@ record_opt_is([], _Last, _Blocks) -> [].
 is_tagged_tuple(#b_var{}=Tuple, Bool,
                 #b_br{bool=Bool,succ=Succ,fail=Fail},
                 Blocks) ->
-    SuccBlk = map_get(Succ, Blocks),
-    is_tagged_tuple_1(SuccBlk, Tuple, Fail, Blocks);
+    #b_blk{is=Is,last=Last} = map_get(Succ, Blocks),
+    case is_tagged_tuple_1(Is, Last, Blocks) of
+        {yes,Fail,Tuple,Arity,Tag} ->
+            {yes,Arity,Tag};
+        _ ->
+            no
+    end;
 is_tagged_tuple(_, _, _, _) -> no.
 
-is_tagged_tuple_1(#b_blk{is=Is,last=Last}, Tuple, Fail, Blocks) ->
-    case Is of
-        [#b_set{op={bif,tuple_size},dst=ArityVar,
-                args=[#b_var{}=Tuple]},
-         #b_set{op={bif,'=:='},
-                dst=Bool,
-                args=[ArityVar, #b_literal{val=ArityVal}=Arity]}]
-        when is_integer(ArityVal) ->
-            case Last of
-                #b_br{bool=Bool,succ=Succ,fail=Fail} ->
-                    SuccBlk = map_get(Succ, Blocks),
-                    case is_tagged_tuple_2(SuccBlk, Tuple, Fail) of
-                        no ->
-                            no;
-                        {yes,Tag} ->
-                            {yes,Arity,Tag}
-                    end;
-                _ ->
-                    no
+is_tagged_tuple_1(Is, Last, Blocks) ->
+    case {Is,Last} of
+        {[#b_set{op={bif,tuple_size},dst=ArityVar,
+                 args=[#b_var{}=Tuple]},
+          #b_set{op={bif,'=:='},
+                 dst=Bool,
+                 args=[ArityVar, #b_literal{val=ArityVal}=Arity]}],
+         #b_br{bool=Bool,succ=Succ,fail=Fail}}
+          when is_integer(ArityVal) ->
+            SuccBlk = map_get(Succ, Blocks),
+            case is_tagged_tuple_2(SuccBlk, Tuple, Fail) of
+                no ->
+                    no;
+                {yes,Tag} ->
+                    {yes,Fail,Tuple,Arity,Tag}
             end;
         _ ->
             no
@@ -2174,6 +2184,46 @@ insert_def_is([#b_set{op=Op}=I|Is]=Is0, V, Def) ->
 insert_def_is([], _V, Def) ->
     [Def].
 
+%%%
+%%% Order consecutive get_tuple_element instructions in ascending
+%%% position order. This will give the loader more opportunities
+%%% for combining get_tuple_element instructions.
+%%%
+
+ssa_opt_get_tuple_element({#st{ssa=Blocks0}=St, FuncDb}) ->
+    Blocks = opt_get_tuple_element(maps:to_list(Blocks0), Blocks0),
+    {St#st{ssa=Blocks}, FuncDb}.
+
+opt_get_tuple_element([{L,#b_blk{is=Is0}=Blk0}|Bs], Blocks) ->
+    case opt_get_tuple_element_is(Is0, false, []) of
+        {yes,Is} ->
+            Blk = Blk0#b_blk{is=Is},
+            opt_get_tuple_element(Bs, Blocks#{L:=Blk});
+        no ->
+            opt_get_tuple_element(Bs, Blocks)
+    end;
+opt_get_tuple_element([], Blocks) -> Blocks.
+
+opt_get_tuple_element_is([#b_set{op=get_tuple_element,
+                                 args=[#b_var{}=Src,_]}=I0|Is0],
+                         _AnyChange, Acc) ->
+    {GetIs0,Is} = collect_get_tuple_element(Is0, Src, [I0]),
+    GetIs1 = sort([{Pos,I} || #b_set{args=[_,Pos]}=I <- GetIs0]),
+    GetIs = [I || {_,I} <- GetIs1],
+    opt_get_tuple_element_is(Is, true, reverse(GetIs, Acc));
+opt_get_tuple_element_is([I|Is], AnyChange, Acc) ->
+    opt_get_tuple_element_is(Is, AnyChange, [I|Acc]);
+opt_get_tuple_element_is([], AnyChange, Acc) ->
+    case AnyChange of
+        true -> {yes,reverse(Acc)};
+        false -> no
+    end.
+
+collect_get_tuple_element([#b_set{op=get_tuple_element,
+                                  args=[Src,_]}=I|Is], Src, Acc) ->
+    collect_get_tuple_element(Is, Src, [I|Acc]);
+collect_get_tuple_element(Is, _Src, Acc) ->
+    {Acc,Is}.
 
 %%%
 %%% Common utilities.