Merge branch 'bjorn/compiler/maps-comparison/OTP-12456' into maint

* bjorn/compiler/maps-comparison/OTP-12456:
  Correct unsafe optimization of '==' and '/='

2 files changed, 15 insertions, 0 deletions

diff --git a/lib/compiler/src/sys_core_fold.erl b/lib/compiler/src/sys_core_fold.erl
index f4f5c3f361..ed8f609082 100644
--- a/lib/compiler/src/sys_core_fold.erl
+++ b/lib/compiler/src/sys_core_fold.erl
@@ -1229,6 +1229,11 @@ is_non_numeric([H|T]) ->
     is_non_numeric(H) andalso is_non_numeric(T);
 is_non_numeric(Tuple) when is_tuple(Tuple) ->
     is_non_numeric_tuple(Tuple, tuple_size(Tuple));
+is_non_numeric(Map) when is_map(Map) ->
+    %% Note that 17.x and 18.x compare keys in different ways.
+    %% Be very conservative -- require that both keys and values
+    %% are non-numeric.
+    is_non_numeric(maps:to_list(Map));
 is_non_numeric(Num) when is_number(Num) ->
     false;
 is_non_numeric(_) -> true.
diff --git a/lib/compiler/test/core_fold_SUITE.erl b/lib/compiler/test/core_fold_SUITE.erl
index 9c7e97a1bf..2de17e7653 100644
--- a/lib/compiler/test/core_fold_SUITE.erl
+++ b/lib/compiler/test/core_fold_SUITE.erl
@@ -210,6 +210,16 @@ eq(Config) when is_list(Config) ->
     ?line ?CMP_DIFF(a, [a]),
     ?line ?CMP_DIFF(a, {1,2,3}),
 
+    ?CMP_SAME(#{a=>1.0,b=>2}, #{b=>2.0,a=>1}),
+    ?CMP_SAME(#{a=>[1.0],b=>[2]}, #{b=>[2.0],a=>[1]}),
+
+    %% The rule for comparing keys are different in 17.x and 18.x.
+    %% Just test that the results are consistent.
+    Bool = id(#{1=>a}) == id(#{1.0=>a}),	%Unoptimizable.
+    Bool = id(#{1=>a}) == #{1.0=>a},		%Optimizable.
+    Bool = #{1=>a} == #{1.0=>a},		%Optimizable.
+    io:format("Bool = ~p\n", [Bool]),
+
     ok.
 
 %% OTP-7117.