Merge pull request #7172 from bjorng/bjorn/compiler/fix-min-max-bool/GH-7170

Eliminate compiler crash in beam_ssa_codegen

2 files changed, 46 insertions, 3 deletions

diff --git a/lib/compiler/src/beam_ssa_codegen.erl b/lib/compiler/src/beam_ssa_codegen.erl
index c4708e9b11..9f6169829b 100644
--- a/lib/compiler/src/beam_ssa_codegen.erl
+++ b/lib/compiler/src/beam_ssa_codegen.erl
@@ -1450,6 +1450,12 @@ cg_copy_1([], _St) -> [].
                           element(1, Val) =:= atom orelse
                           element(1, Val) =:= literal)).
 
+bif_to_test(min, Args, Fail, St) ->
+    %% The min/2 and max/2 BIFs can only be rewritten to tests when
+    %% both arguments are known to be booleans.
+    bif_to_test('and', Args, Fail, St);
+bif_to_test(max, Args, Fail, St) ->
+    bif_to_test('or', Args, Fail, St);
 bif_to_test('or', [V1,V2], {f,Lbl}=Fail, St0) when Lbl =/= 0 ->
     {SuccLabel,St} = new_label(St0),
     {[{test,is_eq_exact,{f,SuccLabel},[V1,{atom,false}]},
diff --git a/lib/compiler/test/bif_SUITE.erl b/lib/compiler/test/bif_SUITE.erl
index fc1d9ddfc0..e58db29114 100644
--- a/lib/compiler/test/bif_SUITE.erl
+++ b/lib/compiler/test/bif_SUITE.erl
@@ -25,7 +25,8 @@
 	 init_per_group/2,end_per_group/2,
 	 beam_validator/1,trunc_and_friends/1,cover_safe_and_pure_bifs/1,
          cover_trim/1,
-         head_tail/1]).
+         head_tail/1,
+         min_max/1]).
 
 suite() ->
     [{ct_hooks,[ts_install_cth]}].
@@ -34,12 +35,13 @@ all() ->
     [{group,p}].
 
 groups() ->
-    [{p,[parallel],
+    [{p,test_lib:parallel(),
       [beam_validator,
        trunc_and_friends,
        cover_safe_and_pure_bifs,
        cover_trim,
-       head_tail
+       head_tail,
+       min_max
       ]}].
 
 init_per_suite(Config) ->
@@ -192,5 +194,40 @@ tail_case() ->
         X -> {X, ok}
     end.
 
+min_max(_Config) ->
+    False = id(false),
+    True = id(true),
+
+    false = bool_min_false(False, False),
+    false = bool_min_false(False, True),
+    false = bool_min_false(True, False),
+    true = bool_min_true(True, True),
+
+    false = bool_max_false(False, False),
+    true = bool_max_true(False, True),
+    true = bool_max_true(True, False),
+    true = bool_max_true(True, True),
+
+    ok.
+
+%% GH-7170: The following functions would cause a crash in
+%% beam_ssa_codegen.
+
+bool_min_false(A, B) when is_boolean(A), is_boolean(B) ->
+    false = min(A, B).
+
+bool_min_true(A, B) when is_boolean(A), is_boolean(B) ->
+    true = min(A, B).
+
+bool_max_false(A, B) when is_boolean(A), is_boolean(B) ->
+    false = max(A, B).
+
+bool_max_true(A, B) when is_boolean(A), is_boolean(B) ->
+    true = max(A, B).
+
+%%%
+%%% Common utilities.
+%%%
+
 id(I) ->
     I.