From e01f6da1b8e7de19f90c7cb21b3cd1ff2ab29cb7 Mon Sep 17 00:00:00 2001
From: Emanuel Peter <epeter@openjdk.org>
Date: Tue, 16 Jan 2024 10:15:00 +0000
Subject: [PATCH] 8320175: [BACKOUT] 8316533: C2 compilation fails with
 assert(verify(phase)) failed: missing Value() optimization

Reviewed-by: thartmann, chagedorn
---
 src/hotspot/share/opto/subtypenode.cpp        | 12 ----
 .../types/TestSubTypeOfAbstractClass.java     | 64 -------------------
 2 files changed, 76 deletions(-)
 delete mode 100644 test/hotspot/jtreg/compiler/types/TestSubTypeOfAbstractClass.java

diff --git a/src/hotspot/share/opto/subtypenode.cpp b/src/hotspot/share/opto/subtypenode.cpp
index 1011cb54245..393585d453c 100644
--- a/src/hotspot/share/opto/subtypenode.cpp
+++ b/src/hotspot/share/opto/subtypenode.cpp
@@ -43,18 +43,6 @@ const Type* SubTypeCheckNode::sub(const Type* sub_t, const Type* super_t) const
     if (!superklass->is_interface() && superklass->is_abstract() &&
         !superklass->as_instance_klass()->has_subklass()) {
       Compile::current()->dependencies()->assert_leaf_type(superklass);
-      if (subk->is_same_java_type_as(superk) && !sub_t->maybe_null()) {
-        // The super_t has no subclasses, and sub_t has the same type and is not null,
-        // hence the check should always evaluate to EQ. However, this is an impossible
-        // situation since super_t is also abstract, and hence sub_t cannot have the
-        // same type and be non-null.
-        // Still, if the non-static method of an abstract class without subclasses is
-        // force-compiled, the Param0 has the self/this pointer with NotNull. This
-        // method would now never be called, because of the leaf-type dependency. Hence,
-        // just for consistency with verification, we return EQ.
-        return TypeInt::CC_EQ;
-      }
-      // subk is either a supertype of superk, or null. In either case, superk is a subtype.
       return TypeInt::CC_GT;
     }
   }
diff --git a/test/hotspot/jtreg/compiler/types/TestSubTypeOfAbstractClass.java b/test/hotspot/jtreg/compiler/types/TestSubTypeOfAbstractClass.java
deleted file mode 100644
index 63274b86e72..00000000000
--- a/test/hotspot/jtreg/compiler/types/TestSubTypeOfAbstractClass.java
+++ /dev/null
@@ -1,64 +0,0 @@
-/*
- * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.  Oracle designates this
- * particular file as subject to the "Classpath" exception as provided
- * by Oracle in the LICENSE file that accompanied this code.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- */
-
-/**
- * @test
- * @bug 8316533
- * @summary Oop of abstract class A with no subclass is subtype checked after null-check
- * @run driver compiler.types.TestSubTypeOfAbstractClass
- */
-
-/**
- * @test
- * @bug 8316533
- * @summary Oop of abstract class A is subtype checked after null-check
- * @requires vm.compiler2.enabled
- * @run main/othervm -XX:CompileCommand=compileonly,*A::test
- *                   -Xcomp -XX:+IgnoreUnrecognizedVMOptions -XX:+StressReflectiveCode
- *                   compiler.types.TestSubTypeOfAbstractClass
- */
-
-package compiler.types;
-
-public class TestSubTypeOfAbstractClass {
-
-    abstract class A {
-        public static A get_null() {
-            return null;
-        }
-
-        public static boolean test() {
-            // NullCheck -> CastPP with type A:NotNull
-            // But A is abstract with no subclass, hence this type is impossible
-            return get_null() instanceof A;
-        }
-    }
-
-    public static void main(String[] args) {
-        for (int i = 0; i < 10_000; i++ ) {
-            A.test();
-        }
-    }
-}