Suggested clean ups and simplifications

Note that the checks before calling make_refill/4 are not necessary.

lib/compiler/src/v3_core.erl

@@ -1654,7 +1654,7 @@ lc_tq1(Line, E, [#igen{anno=#a{anno=GA}=GAnno,
     AccClauseNoGuards = if
                             AccGuard =:= [] ->
                                 nomatch;
-                            element(1,NomatchMode) =:= skip ->
+                            NomatchMode =:= skip ->
                                 nomatch;
                             true ->
                                 make_clause([compiler_generated|LA],
@@ -1688,27 +1688,31 @@ zip_tq(Line, E, #izip{anno=#a{anno=GA}=GAnno,
     %% Generate the name for the letrec.
     F = #c_var{anno=LA,name={Name,NumGenerators}},
 
-    %% Generate the clauses for the letrec.
+    %% Generate the clauses for the letrec. First, the accumulating
+    %% clause.
     Sc = #iapply{anno=GAnno,op=F,args=TailVars},
     {Lc,Lps,St4} = lc_tq(Line, E, Qs, Sc, St3),
-
     AccClause = make_clause(LA, AccPats, AccGuard, Lps++[Lc]),
-    %% If all generators are strict, no skipping is possible.
-    AccClauseNoGuards = case NomatchTotal of
-                            strict -> nomatch;
-                            _ -> make_clause([skip_clause,compiler_generated|LA],
-                                                SkipPats, [], [Sc])
-                        end,
-    TailClause = make_clause(LA, TailPats, [], [Mc]),
-    RefillClause =
-        case all(fun(X) -> X =:= nomatch end, RefillPats0) of
-            true ->
-                %% There are no map generators.
-                [nomatch];
-            false ->
-                make_refill(RefillPats0, 0, RefillAs, {TailVars, LA, [], Sc})
+
+    %% Generate the skip clause unless all generators are strict, in
+    %% which case no skipping is possible.
+    AccClauseNoGuards =
+        case NomatchTotal of
+            strict ->
+                nomatch;
+            _ ->
+                make_clause([skip_clause,compiler_generated|LA],
+                            SkipPats, [], [Sc])
         end,
-    Cs0 = [AccClause, AccClauseNoGuards, TailClause]++RefillClause,
+
+    %% Generate the clause testing for empty generators.
+    TailClause = make_clause(LA, TailPats, [], [Mc]),
+
+    %% Generate refill clauses for map generators.
+    RefillClauses = make_refill(RefillPats0, 0, RefillAs, {TailVars, LA, [], Sc}),
+
+    %% Gather clauses.
+    Cs0 = [AccClause, AccClauseNoGuards, TailClause | RefillClauses],
     Cs = [C || C <- Cs0, C =/= nomatch],
 
     Fc = bad_generators(FcVars, hd(Args), lc, bad_generators),
@@ -1851,32 +1855,38 @@ bzip_tq1(Line, E, #izip{anno=#a{anno=_GA}=GAnno,
     %% Generate the name for the letrec.
     F = #c_var{anno=LA,name={Name,Arity}},
 
-    %% Generate the clauses for the letrec.
+    %% Generate the clauses for the letrec. First, the accumulating
+    %% clause.
     BinAccVar = last(CallVars),
     Sc = #iapply{anno=GAnno,op=F,args=TailVars++[BinAccVar]},
     {Bc,Bps,St4} = bc_tq1(Line, E, Qs, BinAccVar, St3),
     Body = Bps++[#iset{var=hd(CallVars), arg=Bc}, Sc],
     AccClause = make_clause(LA, AccPats++[Mc], AccGuard, Body),
-    %% If all generators are strict, no skipping is possible.
-    AccClauseNoGuards = case NomatchTotal of
-                            strict -> nomatch;
-                            _ -> make_clause([skip_clause,compiler_generated|LA],
-                                                SkipPats++[Mc], [], [Sc])
-                        end,
-    TailClause = make_clause(LA, TailPats++[Mc], [], [Mc]),
-    RefillClause =
-        case all(fun(X) -> X =:= nomatch end, RefillPats0) of
-            true ->
-                %% There are no map generators.
-                [nomatch];
-            false ->
-                make_refill(RefillPats0, 0, RefillAs, {TailVars, LA, [Mc], Sc})
+
+    %% Generate the skip clause unless all generators are strict, in
+    %% which case no skipping is possible.
+    AccClauseNoGuards =
+        case NomatchTotal of
+            strict ->
+                nomatch;
+            _ ->
+                make_clause([skip_clause,compiler_generated|LA],
+                            SkipPats++[Mc], [], [Sc])
         end,
-    Cs0 = [AccClause, AccClauseNoGuards, TailClause]++RefillClause,
+
+    %% Generate the clause testing for empty generators.
+    TailClause = make_clause(LA, TailPats++[Mc], [], [Mc]),
+
+    %% Generate refill clauses for map generators.
+    RefillClauses = make_refill(RefillPats0, 0, RefillAs, {TailVars, LA, [Mc], Sc}),
+
+    %% Gather clauses.
+    Cs0 = [AccClause, AccClauseNoGuards, TailClause | RefillClauses],
     Cs = [C || C <- Cs0, C =/= nomatch],
 
     Fc = bad_generators(FcVars, hd(Args), bc, bad_generators),
     Fun = #ifun{anno=GAnno,id=[],vars=CallVars,clauses=Cs,fc=Fc},
+
     %% Inlining would disable the size calculation optimization for
     %% bs_init_writable.
     {#iletrec{anno=LAnno#a{anno=[list_comprehension,no_inline|LA]},
@@ -2020,10 +2030,10 @@ preprocess_zip_generators([], Zip) ->
     Zip.
 
 get_nomatch_total(NomatchModes) ->
-    case lists:all(fun(X) -> X =:= skip end, NomatchModes) of
+    case all(fun(X) -> X =:= skip end, NomatchModes) of
         true -> skip;
         false ->
-            case lists:any(fun(X) -> X =:= skip end, NomatchModes) of
+            case any(fun(X) -> X =:= skip end, NomatchModes) of
                 true -> mixed;
                 false -> strict
             end
@@ -2732,7 +2742,6 @@ bad_generator(Ps, Generator, Arg) ->
     L = [#c_literal{val=bad_generator}, Generator],
     bad_generator_common(L, Ps, Arg).
 
-
 bad_generators(Ps, Arg, bc, ErrorType) ->
     T1 = #c_tuple{es=droplast(Ps)},
     L = [#c_literal{val=ErrorType}, T1],
@@ -4430,7 +4439,7 @@ is_simple(_) -> false.
 
 -spec is_simple_list([cerl:cerl()]) -> boolean().
 
-is_simple_list(Es) -> lists:all(fun is_simple/1, Es).
+is_simple_list(Es) -> all(fun is_simple/1, Es).
 
 insert_nif_start([VF={V,F=#c_fun{body=Body}}|Funs]) ->
     case Body of