beam_jump: Don't move a block which can be entered via a fallthrough

beam_jump moves short code sequences ending in an instruction that causes
an exception to the end of the function, in the hope that a jump around
the moved blocked can be replaced with a fallthrough. Therefore, moving
a block that is entered via a fallthrough defeats the purpose of the
optimization.

Also add two more test cases for the beam_receive module to ensure that
all lines are still covered.

2 files changed, 34 insertions, 0 deletions

diff --git a/lib/compiler/test/receive_SUITE_data/ref_opt/yes_10.erl b/lib/compiler/test/receive_SUITE_data/ref_opt/yes_10.erl
new file mode 100644
index 0000000000..7ce6e6103c
--- /dev/null
+++ b/lib/compiler/test/receive_SUITE_data/ref_opt/yes_10.erl
@@ -0,0 +1,13 @@
+-module(yes_10).
+-compile(export_all).
+
+?MODULE() ->
+    ok.
+
+f() ->
+    Ref = make_ref(),
+    receive
+	%% Artifical example to cover more code in beam_receive.
+	{X,Y} when Ref =/= X, Ref =:= Y ->
+	    ok
+    end.
diff --git a/lib/compiler/test/receive_SUITE_data/ref_opt/yes_11.erl b/lib/compiler/test/receive_SUITE_data/ref_opt/yes_11.erl
new file mode 100644
index 0000000000..62f439fc42
--- /dev/null
+++ b/lib/compiler/test/receive_SUITE_data/ref_opt/yes_11.erl
@@ -0,0 +1,21 @@
+-module(yes_11).
+-compile(export_all).
+
+?MODULE() ->
+    ok.
+
+%% Artifical example to cover more code in beam_receive.
+do_call(Process, Request) ->
+    Mref = erlang:monitor(process, Process),
+    Process ! Request,
+    receive
+	{X,Y,Z} when Mref =/= X, Z =:= 42, Mref =:= Y ->
+	    error;
+	{X,Y,_} when Mref =/= X, Mref =:= Y ->
+	    error;
+	{Mref, Reply} ->
+	    erlang:demonitor(Mref, [flush]),
+	    {ok, Reply};
+	{'DOWN', Mref, _, _, _} ->
+	    error
+    end.