Fix unsafe optimizations where guard tests could be removed

A repeated test could be optimized away. Example:

    bar(A) ->
        if is_bitstring(A) ->
                if is_binary(A) ->
                        binary;
                   true ->
                        bitstring
                end;
           true ->
                other
        end.

In the example, the `is_binary/1` test would be optimized away,
basically turning the example into:

    bar(A) ->
        if is_bitstring(A) ->
                bitstring;
           true ->
                other
        end.

Thanks user Marcus Kruse in the Elixir forum for noticing this bug.

1 files changed, 2 insertions, 10 deletions

diff --git a/lib/compiler/src/beam_ssa_dead.erl b/lib/compiler/src/beam_ssa_dead.erl
index bb43a550ae..e220a89ded 100644
--- a/lib/compiler/src/beam_ssa_dead.erl
+++ b/lib/compiler/src/beam_ssa_dead.erl
@@ -680,11 +680,8 @@ will_succeed_test(is_list, is_nonempty_list) ->
     maybe;
 will_succeed_test(is_nonempty_list, is_list) ->
     yes;
-will_succeed_test(T1, T2) ->
-    case is_numeric_test(T1) andalso is_numeric_test(T2) of
-        true -> maybe;
-        false -> no
-    end.
+will_succeed_test(_T1, _T2) ->
+    maybe.
 
 will_succeed_1('=:=', A, '<', B) ->
     if
@@ -769,11 +766,6 @@ will_succeed_vars('==', Val1, '/=', Val2) when Val1 == Val2 -> no;
 
 will_succeed_vars(_, _, _, _) -> maybe.
 
-is_numeric_test(is_float) -> true;
-is_numeric_test(is_integer) -> true;
-is_numeric_test(is_number) -> true;
-is_numeric_test(_) -> false.
-
 eval_type_test(Test, Arg) ->
     case eval_type_test_1(Test, Arg) of
         true -> yes;