Fix a rare crash when matching on literal maps

When matching on a literal map, the map is placed into the general
scratch register first. This is fine in isolation, but when the
key to be matched was in a Y register it would also be placed in
the scratch register, overwriting the map and crashing the
emulator.

1 files changed, 11 insertions, 0 deletions

diff --git a/erts/emulator/test/map_SUITE.erl b/erts/emulator/test/map_SUITE.erl
index f93c637650..d0a6763fe5 100644
--- a/erts/emulator/test/map_SUITE.erl
+++ b/erts/emulator/test/map_SUITE.erl
@@ -3080,8 +3080,19 @@ y_regs(Config) when is_list(Config) ->
 
     true = is_map(Map2) andalso is_map(Map4),
 
+    gurka = y_regs_literal(0),
+    gaffel = y_regs_literal(1),
+
     ok.
 
+y_regs_literal(Key) when is_integer(Key) ->
+    %% Forces the key to be placed in a Y register.
+    lists:seq(1, 2),
+    case is_map_key(Key, #{ 0 => 0 }) of
+        true -> gurka;
+        false -> gaffel
+    end.
+
 y_regs_update(Map0, Val0) ->
     Val1 = {t,Val0},
     K1 = id({key,1}),