8232874: Add missing test for 8230062
authorchagedorn
Wed, 23 Oct 2019 12:17:14 +0200
changeset 58750 c8d42aa9359a
parent 58749 cfdd7ef808d9
child 58751 0f882d53c204
8232874: Add missing test for 8230062 Summary: Adds a missing test which verifies the bug fix of 8230062. Reviewed-by: roland, thartmann
test/hotspot/jtreg/compiler/loopopts/superword/SuperWordIntermediateUse.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/hotspot/jtreg/compiler/loopopts/superword/SuperWordIntermediateUse.java	Wed Oct 23 12:17:14 2019 +0200
@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2019, 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.
+ *
+ * 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 8230062
+ * @summary The IR of this test contains a reduction chain which corresponds to a pack in which the 2nd last element has a usage outside of the optimized loop.
+ *
+ * @run main/othervm -Xbatch -XX:CompileCommand=compileonly,compiler.loopopts.superword.SuperWordIntermediateUse::test
+ *      compiler.loopopts.superword.SuperWordIntermediateUse
+ */
+
+package compiler.loopopts.superword;
+
+public class SuperWordIntermediateUse {
+
+    private int iFld;
+    private int[] iArr = new int[1024];
+
+    public void test() {
+        int local = 4;
+
+        /**
+         * Before unrolling this loop:
+         * iFld:   AddI 1 = -85 + Phi 1
+         * local:  MulI 2 = Phi 1 * LoadI 3
+         *
+         * This loop is now unrolled. 'local' is a reduction. The loop is first copied:
+         * iFldCopy:  AddI C1 = -85 + Phi C1
+         * localCopy: MulI C2 = Phi C1 * LoadI C3
+         *
+         * iFld:   AddI 1 = -85 + Phi 1
+         * local:  MulI 2 = Phi 1 * LoadI 3
+         *
+         * Then, the unnecessary nodes like phis are removed from the original loop by igvn:
+         * (iFldCopy:  AddI C1 = -85 + Phi C1) field store optimized away
+         * localCopy: MulI C2 = Phi C1 * LoadI C3
+         *
+         * iFld:   AddI 1 = -85 + MulI C2
+         * local:  MulI 2 = MulI C2 * LoadI 3 -> Input into Phi C1
+         *
+         *  As a result AddI 1 has an input from MulI C2 which isn't the last operation in the reduction chain
+         *  Phi C1 -> MulI C2 -> MulI 2 -> Phi C1 and therefore not the last element in a pack.
+         *  Additionally, AddI 1 does not belong to the loop being optimized: The store node for iFld is put outside of the loop being optimized.
+         *  This triggers the assertion bug when unrolled at least 4 times which creates packs of at least size 4.
+         */
+        for (int i = 0; i < 1024; i++) {
+            iFld = -85;
+            iFld = iFld + local;
+            local = local * iArr[i];
+            iArr[i] = 3; // Just used to trigger SuperWord optimization
+        }
+    }
+
+    public static void main(String[] strArr) {
+        SuperWordIntermediateUse instance = new SuperWordIntermediateUse();
+        for (int i = 0; i < 1000; i++) {
+            instance.test();
+        }
+    }
+}