File 2934-Eliminate-use-of-sets-size-1-when-sets-is_empty-1-wi.patch of Package erlang

From 6b638b179b79011af87a2b5c4eab7dd0cc6ef2b7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Sat, 20 Feb 2021 09:13:04 +0100
Subject: [PATCH 4/6] Eliminate use of sets:size/1 when sets:is_empty/1 will
 work

---
 lib/compiler/src/beam_ssa_opt.erl   | 20 ++++++++++----------
 lib/compiler/src/beam_ssa_throw.erl |  6 +++---
 lib/compiler/src/v3_kernel.erl      |  6 +++---
 3 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/lib/compiler/src/beam_ssa_opt.erl b/lib/compiler/src/beam_ssa_opt.erl
index 9d65c6bebc..486d33ef05 100644
--- a/lib/compiler/src/beam_ssa_opt.erl
+++ b/lib/compiler/src/beam_ssa_opt.erl
@@ -96,11 +96,11 @@ fixpoint(_FuncIds, _Order, _Passes, StMap, FuncDb, 0) ->
 fixpoint(FuncIds0, Order0, Passes, StMap0, FuncDb0, N) ->
     {StMap, FuncDb} = phase(FuncIds0, Passes, StMap0, FuncDb0),
     Repeat = changed(FuncIds0, FuncDb0, FuncDb, StMap0, StMap),
-    case sets:size(Repeat) of
-        0 ->
+    case sets:is_empty(Repeat) of
+        true ->
             %% No change. Fixpoint reached.
             {StMap, FuncDb};
-        _ ->
+        false ->
             %% Repeat the optimizations for functions whose code has
             %% changed or for which there is potentially updated type
             %% information.
@@ -1436,9 +1436,9 @@ do_reduce_try([{L, Blk} | Bs]=Bs0, Ws0) ->
             %% This block is not reachable from the block with the
             %% `new_try_tag` instruction. Retain it. There is no
             %% need to check it for safety.
-            case sets:size(Ws0) of
-                0 -> Bs0;
-                _ -> [{L, Blk} | do_reduce_try(Bs, Ws0)]
+            case sets:is_empty(Ws0) of
+                true -> Bs0;
+                false -> [{L, Blk} | do_reduce_try(Bs, Ws0)]
             end;
         true ->
             Ws1 = sets:del_element(L, Ws0),
@@ -1464,7 +1464,7 @@ do_reduce_try([{L, Blk} | Bs]=Bs0, Ws0) ->
             end
     end;
 do_reduce_try([], Ws) ->
-    0 = sets:size(Ws),                     %Assertion.
+    true = sets:is_empty(Ws),                   %Assertion.
     [].
 
 reduce_try_is([#b_set{op=kill_try_tag}|Is], Acc) ->
@@ -1531,10 +1531,10 @@ trim_try([{L, Blk} | Bs], Unreachable0, Killed, Acc) ->
     Unreachable = sets:subtract(Unreachable0, Successors),
     trim_try(Bs, Unreachable, Killed, [{L, Blk} | Acc]);
 trim_try([], _Unreachable, Killed, Acc0) ->
-    case sets:size(Killed) of
-        0 ->
+    case sets:is_empty(Killed) of
+        true ->
             Acc0;
-        _ ->
+        false ->
             %% Remove all `kill_try_tag` instructions referencing removed
             %% try/catches.
             [{L, Blk#b_blk{is=trim_try_is(Is0, Killed)}} ||
diff --git a/lib/compiler/src/beam_ssa_throw.erl b/lib/compiler/src/beam_ssa_throw.erl
index fc0d53e6ab..cf742ec6ce 100644
--- a/lib/compiler/src/beam_ssa_throw.erl
+++ b/lib/compiler/src/beam_ssa_throw.erl
@@ -106,10 +106,10 @@ scan_1([], Gst) ->
          tlh_edges=Edges,
          throws=Throws} = Gst,
 
-    case sets:size(Throws) of
-        0 ->
+    case sets:is_empty(Throws) of
+        true ->
             no_throws;
-        _ ->
+        false ->
             TLHs = propagate_tlhs(gb_trees:to_list(Roots), Edges, #{}),
             {Throws, TLHs}
     end.
diff --git a/lib/compiler/src/v3_kernel.erl b/lib/compiler/src/v3_kernel.erl
index 40cf1c276c..2bb340e26d 100644
--- a/lib/compiler/src/v3_kernel.erl
+++ b/lib/compiler/src/v3_kernel.erl
@@ -1468,10 +1468,10 @@ partition_keys(#ialias{pat=Map}=Alias, Ks) ->
 find_key_intersection(Ps) ->
     Sets = [sets:from_list(Ks, [{version, 2}]) || Ks <- Ps],
     Intersection = sets:intersection(Sets),
-    case sets:size(Intersection) of
-        0 ->
+    case sets:is_empty(Intersection) of
+        true ->
             none;
-        _ ->
+        false ->
             All = all(fun (Kset) -> Kset =:= Intersection end, Sets),
             case All of
                 true ->
-- 
2.26.2