8343137: C2: VerifyLoopOptimizations fails with "Was reachable in only one"

Reviewed-by: thartmann, kvn

Author: chhagedorn

src/hotspot/share/opto/loopnode.cpp

@@ -4488,7 +4488,9 @@ void PhaseIdealLoop::eliminate_useless_template_assertion_predicates(Unique_Node
     OpaqueTemplateAssertionPredicateNode* opaque_node =
         C->template_assertion_predicate_opaq_node(i - 1)->as_OpaqueTemplateAssertionPredicate();
     if (!useful_predicates.member(opaque_node)) { // not in the useful list
-      _igvn.replace_node(opaque_node, _igvn.intcon(1));
+      ConINode* one = _igvn.intcon(1);
+      set_ctrl(one, C->root());
+      _igvn.replace_node(opaque_node, one);
     }
   }
 }

test/hotspot/jtreg/compiler/predicates/TestAssertionPredicateDoesntConstantFold.java renamed to test/hotspot/jtreg/compiler/predicates/assertion/TestAssertionPredicateDoesntConstantFold.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2024, 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 8343137
+ * @requires vm.debug == true & vm.compiler2.enabled
+ * @summary Test that set_ctrl() is properly set for true constant when folding useless Template Assertion Predicate.
+ * @run main/othervm -Xcomp -XX:+VerifyLoopOptimizations
+ *                   -XX:CompileCommand=compileonly,compiler.predicates.assertion.TestMissingSetCtrlForTrueConstant::test
+ *                   compiler.predicates.assertion.TestMissingSetCtrlForTrueConstant
+ */
+
+package compiler.predicates.assertion;
+
+public class TestMissingSetCtrlForTrueConstant {
+    static long iFld;
+    static int[] iArrFld = new int[100];
+    static double[] dArrFld = new double[100];
+
+    public static void main(String[] strArr) {
+        test();
+    }
+
+    static void test() {
+        long l = 34;
+        for (int i = 78; i > 8; --i) {
+            switch (i) {
+                case 24:
+                    l += iFld - 34;
+                case 25:
+                    iFld = iArrFld[i] += i;
+            }
+            dArrFld[i + 1] += i;
+        }
+    }
+}

test/hotspot/jtreg/compiler/predicates/assertion/TestMissingSetCtrlForTrueConstant.java

@@ -29,14 +29,14 @@
  *          completely with JDK-8288981 and 8314116 just mitigates the problem.
  * @requires vm.compiler2.enabled
  * @run main/othervm -Xbatch -XX:-TieredCompilation
- *                   -XX:CompileCommand=compileonly,compiler.predicates.TestTemplateAssertionPredicateNotRemoved::*
- *                   compiler.predicates.TestTemplateAssertionPredicateNotRemoved
+ *                   -XX:CompileCommand=compileonly,compiler.predicates.assertion.TestTemplateAssertionPredicateNotRemoved::*
+ *                   compiler.predicates.assertion.TestTemplateAssertionPredicateNotRemoved
  * @run main/othervm -Xbatch -XX:-TieredCompilation -XX:LoopMaxUnroll=0
- *                   -XX:CompileCommand=compileonly,compiler.predicates.TestTemplateAssertionPredicateNotRemoved::*
- *                   compiler.predicates.TestTemplateAssertionPredicateNotRemoved
+ *                   -XX:CompileCommand=compileonly,compiler.predicates.assertion.TestTemplateAssertionPredicateNotRemoved::*
+ *                   compiler.predicates.assertion.TestTemplateAssertionPredicateNotRemoved
  */
 
-package compiler.predicates;
+package compiler.predicates.assertion;
 
 public class TestTemplateAssertionPredicateNotRemoved {
     static int[] iArrFld = new int[10];

test/hotspot/jtreg/compiler/predicates/TestTemplateAssertionPredicateNotRemoved.java renamed to test/hotspot/jtreg/compiler/predicates/assertion/TestTemplateAssertionPredicateNotRemoved.java

@@ -27,11 +27,11 @@
  * @bug 8342287
  * @summary Test that a fail path projection of a Template Assertion Predicate is not treated as success path projection.
  * @run main/othervm -XX:-TieredCompilation -Xbatch
- *                   -XX:CompileCommand=compileonly,compiler.predicates.TestTemplateAssertionPredicateWithTwoUCTs::test
- *                   compiler.predicates.TestTemplateAssertionPredicateWithTwoUCTs
+ *                   -XX:CompileCommand=compileonly,compiler.predicates.assertion.TestTemplateAssertionPredicateWithTwoUCTs::test
+ *                   compiler.predicates.assertion.TestTemplateAssertionPredicateWithTwoUCTs
  */
 
-package compiler.predicates;
+package compiler.predicates.assertion;
 
 public class TestTemplateAssertionPredicateWithTwoUCTs {
     static int iFld;