Cover more code in beam_jump

The previous optimizations caused some code in beam_jump to
become uncovered. Add tests to cover more code. Also remove
a clause in beam_jump:opt/3 that does not seem possible to
cover anymore (this is safe, because the clause was an
optimization).

2 files changed, 42 insertions, 12 deletions

diff --git a/lib/compiler/src/beam_jump.erl b/lib/compiler/src/beam_jump.erl
index 57329338bf..8b0e3e32f8 100644
--- a/lib/compiler/src/beam_jump.erl
+++ b/lib/compiler/src/beam_jump.erl
@@ -429,16 +429,6 @@ opt([{test,_,{f,L}=Lbl,_}=I|[{jump,{f,L}}|_]=Is], Acc, St) ->
 	    %% as in the jump that follows -- thus it is not needed.
 	    opt(Is, Acc, St)
     end;
-opt([{test,_,{f,L}=Lbl,_}=I|[{label,L}|_]=Is], Acc, St) ->
-    %% Similar to the above, except we have a fall-through rather than jump
-    %%    Test Label Ops
-    %%    label Label
-    case beam_utils:is_pure_test(I) of
-	false ->
-	    opt(Is, [I|Acc], label_used(Lbl, St));
-	true ->
-	    opt(Is, Acc, St)
-    end;
 opt([{test,Test0,{f,L}=Lbl,Ops}=I|[{jump,To}|Is]=Is0], Acc, St) ->
     case is_label_defined(Is, L) of
 	false ->
diff --git a/lib/compiler/test/beam_jump_SUITE.erl b/lib/compiler/test/beam_jump_SUITE.erl
index 40eb6f06c3..759d884dc4 100644
--- a/lib/compiler/test/beam_jump_SUITE.erl
+++ b/lib/compiler/test/beam_jump_SUITE.erl
@@ -22,7 +22,8 @@
 -export([all/0,suite/0,groups/0,init_per_suite/1,end_per_suite/1,
 	 init_per_group/2,end_per_group/2,
 	 undefined_label/1,ambiguous_catch_try_state/1,
-         unsafe_move_elimination/1,build_tuple/1]).
+         unsafe_move_elimination/1,build_tuple/1,
+         coverage/1]).
 
 suite() ->
     [{ct_hooks,[ts_install_cth]}].
@@ -35,7 +36,8 @@ groups() ->
       [undefined_label,
        ambiguous_catch_try_state,
        unsafe_move_elimination,
-       build_tuple
+       build_tuple,
+       coverage
       ]}].
 
 init_per_suite(Config) ->
@@ -126,6 +128,44 @@ do_build_tuple(Message) ->
 	    {Message#message3.id, Res}
     end.
 
+coverage(_Config) ->
+    ok = coverage_1(ok),
+    {error,badarg} = coverage_1({error,badarg}),
+
+    gt = coverage_2(100, 42),
+    le = coverage_2(100, 999),
+    le = coverage_2([], []),
+    gt = coverage_2([], xxx),
+
+    ok.
+
+coverage_1(Var) ->
+    case id(Var) of
+	ok -> ok;
+	Error -> Error
+    end.
+
+%% Cover beam_jump:invert_test(is_ne_exact).
+coverage_2(Pre1, Pre2) ->
+    case
+        case Pre1 == [] of
+            false ->
+                false;
+            true ->
+                Pre2 /= []
+        end
+    of
+        true ->
+            gt;
+        false ->
+            case Pre1 > Pre2 of
+                true ->
+                    gt;
+                false ->
+                    le
+            end
+    end.
+
 
 id(I) ->
     I.