3 files changed, 68 insertions, 3 deletions
diff --git a/lib/compiler/test/beam_utils_SUITE.erl b/lib/compiler/test/beam_utils_SUITE.erl
index ac19305d69..ff0f72d519 100644
--- a/lib/compiler/test/beam_utils_SUITE.erl
+++ b/lib/compiler/test/beam_utils_SUITE.erl
@@ -26,7 +26,7 @@
 	 select/1,y_catch/1,otp_8949_b/1,liveopt/1,coverage/1,
          y_registers/1,user_predef/1,scan_f/1,cafu/1,
          receive_label/1,read_size_file_version/1,not_used/1,
-         is_used_fr/1]).
+         is_used_fr/1,unsafe_is_function/1]).
 -export([id/1]).
 
 suite() -> [{ct_hooks,[ts_install_cth]}].
@@ -53,7 +53,8 @@ groups() ->
        cafu,
        read_size_file_version,
        not_used,
-       is_used_fr
+       is_used_fr,
+       unsafe_is_function
       ]}].
 
 init_per_suite(Config) ->
@@ -570,6 +571,24 @@ is_used_fr(X, Y) ->
         end,
     X ! 1.
 
+%% ERL-778.
+unsafe_is_function(Config) ->
+    {undefined,any} = unsafe_is_function(undefined, any),
+    {ok,any} = unsafe_is_function(fun() -> ok end, any),
+    {'EXIT',{{case_clause,_},_}} = (catch unsafe_is_function(fun(_) -> ok end, any)),
+    ok.
+
+unsafe_is_function(F, M) ->
+    %% There would be an internal consistency failure:
+    %%   Instruction: {bif,is_function,{f,0},[{x,0},{integer,0}],{x,2}}
+    %%   Error:       {uninitialized_reg,{y,0}}:
+
+    NewValue = case is_function(F, 0) of
+                true -> F();
+                false when F =:= undefined -> undefined
+            end,
+    {NewValue,M}.
+
 
 %% The identity function.
 id(I) -> I.
diff --git a/lib/compiler/test/match_SUITE.erl b/lib/compiler/test/match_SUITE.erl
index e3f842b668..72e5356a8d 100644
--- a/lib/compiler/test/match_SUITE.erl
+++ b/lib/compiler/test/match_SUITE.erl
@@ -378,6 +378,13 @@ untuplify(Config) when is_list(Config) ->
     %% We do this to cover sys_core_fold:unalias_pat/1.
     {1,2,3,4,alias,{[1,2],{3,4},alias}} = untuplify_1([1,2], {3,4}, alias),
     error = untuplify_1([1,2], {3,4}, 42),
+
+    %% Test that a previous bug in v3_codegen is gone. (The sinking of
+    %% stack frames into only the case arms that needed them was not always
+    %% safe.)
+    [33, -1, -33, 1] = untuplify_2(32, 65),
+    {33, 1, -33, -1} = untuplify_2(65, 32),
+
     ok.
 
 untuplify_1(A, B, C) ->
@@ -390,6 +397,21 @@ untuplify_1(A, B, C) ->
 	    error
     end.
 
+untuplify_2(V1, V2) ->
+    {D1,D2,D3,D4} =
+        if V1 > V2 ->
+                %% The 1 value was overwritten by the value of V2-V1.
+                {V1-V2,  1,  V2-V1, -1};
+           true ->
+                {V2-V1, -1, V1-V2,  1}
+        end,
+    if
+        D2 > D4 ->
+            {D1, D2, D3, D4};
+        true ->
+            [D1, D2, D3, D4]
+    end.
+
 %% Coverage of beam_dead:shortcut_boolean_label/4.
 shortcut_boolean(Config) when is_list(Config) ->
     false = shortcut_boolean_1([0]),
diff --git a/lib/compiler/test/trycatch_SUITE.erl b/lib/compiler/test/trycatch_SUITE.erl
index 1b7ef4ddb0..8f9cd9ab1e 100644
--- a/lib/compiler/test/trycatch_SUITE.erl
+++ b/lib/compiler/test/trycatch_SUITE.erl
@@ -1189,7 +1189,8 @@ bad_raise(Expr) ->
 test_raise(Expr) ->
     test_raise_1(Expr),
     test_raise_2(Expr),
-    test_raise_3(Expr).
+    test_raise_3(Expr),
+    test_raise_4(Expr).
 
 test_raise_1(Expr) ->
     erase(exception),
@@ -1263,5 +1264,28 @@ do_test_raise_3(Expr) ->
             erlang:raise(exit, {exception,C,E}, Stk)
     end.
 
+test_raise_4(Expr) ->
+    try
+        do_test_raise_4(Expr)
+    catch
+        exit:{exception,C,E,Stk}:Stk ->
+            try
+                Expr()
+            catch
+                C:E:S ->
+                    [StkTop|_] = S,
+                    [StkTop|_] = Stk
+            end
+    end.
+
+do_test_raise_4(Expr) ->
+    try
+        Expr()
+    catch
+        C:E:Stk ->
+            %% Here the stacktrace must be built.
+            erlang:raise(exit, {exception,C,E,Stk}, Stk)
+    end.
+
 
 id(I) -> I.