Merge pull request #6430 from bjorng/bjorn/compiler/ssa_opt_ranges/GH-6427

Eliminate internal error in sub pass ssa_opt_ranges

2 files changed, 47 insertions, 1 deletions

diff --git a/lib/compiler/src/beam_ssa_type.erl b/lib/compiler/src/beam_ssa_type.erl
index 7e74e7e3f7..b293250365 100644
--- a/lib/compiler/src/beam_ssa_type.erl
+++ b/lib/compiler/src/beam_ssa_type.erl
@@ -920,8 +920,20 @@ update_anno_types_1([#b_var{}=V|As], Ts, Index, ArgTypes) ->
     case beam_types:meet(T0, T1) of
         any ->
             update_anno_types_1(As, Ts, Index + 1, ArgTypes);
+        none ->
+            %% This instruction will never be reached. This happens when
+            %% compiling code such as the following:
+            %%
+            %%   f(X) when is_integer(X), 0 =< X, X < 64 ->
+            %%        (X = bnot X) + 1.
+            %%
+            %% The main type optimization sub pass will not find out
+            %% that `(X = bnot X)` will never succeed and that the `+`
+            %% operator is never executed, but this sub pass will.
+            %% This happens very rarely; therefore, don't bother removing
+            %% the unreachable instruction.
+            update_anno_types_1(As, Ts, Index + 1, ArgTypes);
         T ->
-            true = T =/= none,                  %Assertion.
             update_anno_types_1(As, Ts, Index + 1, ArgTypes#{Index => T})
     end;
 update_anno_types_1([_|As], Ts, Index, ArgTypes) ->
diff --git a/lib/compiler/test/beam_type_SUITE.erl b/lib/compiler/test/beam_type_SUITE.erl
index 3439e36236..8bdce54543 100644
--- a/lib/compiler/test/beam_type_SUITE.erl
+++ b/lib/compiler/test/beam_type_SUITE.erl
@@ -119,6 +119,11 @@ integers(_Config) ->
     {'EXIT',{system_limit,_}} = catch do_integers_12(42),
     {'EXIT',{system_limit,_}} = catch do_integers_12([]),
 
+    {'EXIT',{{badmatch,42},_}} = catch do_integers_13(-43),
+    {'EXIT',{{badmatch,0},_}} = catch do_integers_13(-1),
+    {'EXIT',{{badmatch,-1},_}} = catch do_integers_13(0),
+    {'EXIT',{{badmatch,-18},_}} = catch do_integers_13(17),
+
     ok.
 
 do_integers_1(B0) ->
@@ -202,6 +207,35 @@ do_integers_11(V) ->
 do_integers_12(X) ->
     (1 bsl (1 bsl 100)) + X.
 
+%% GH-6427.
+do_integers_13(X) ->
+    try do_integers_13_1(<<X>>) of
+        _ -> error(should_fail)
+    catch
+        C:R:_ ->
+            try do_integers_13_2(X) of
+                _ -> error(should_fail)
+            catch
+                C:R:_ ->
+                    try do_integers_13_3(X) of
+                        _ -> error(should_fail)
+                    catch
+                        C:R:Stk ->
+                            erlang:raise(C, R, Stk)
+                    end
+            end
+    end.
+
+do_integers_13_1(<<X>>) ->
+    <<(X = bnot X)>>.
+
+do_integers_13_2(X) when is_integer(X), -64 < X, X < 64 ->
+    (X = bnot X) + 1.
+
+do_integers_13_3(X) when is_integer(X), -64 < X, X < 64 ->
+    X = bnot X,
+    X + 1.
+
 numbers(_Config) ->
     Int = id(42),
     true = is_integer(Int),