8164102: MethodHandles.countedLoop/4 works incorrect for start/end = Integer.MAX_VALUE

Reviewed-by: redestad

jdk/src/java.base/share/classes/java/lang/invoke/MethodHandleImpl.java

@@ -1934,7 +1934,7 @@ import static jdk.internal.org.objectweb.asm.Opcodes.*;
      * @return whether the counter has reached the limit.
      */
     static boolean countedLoopPredicate(int counter, int limit) {
-        return counter <= limit;
+        return counter < limit;
     }
 
     /**

jdk/src/java.base/share/classes/java/lang/invoke/MethodHandles.java

@@ -4583,7 +4583,8 @@ assertEquals("boojum", (String) catTrace.invokeExact("boo", "jum"));
      *     // assume MH_decrement is a handle to x-1 of type int
      *     MethodHandle[]
      *         indexVar = {start, MH_increment}, // i = start; i = i+1
-     *         loopLimit = {end, null, MH_lessThan, returnVar }, // i<end
+     *         loopLimit = {end, null,
+     *                       filterArgument(MH_lessThan, 0, MH_decrement), returnVar}, // i-1<end
      *         bodyClause = {init,
      *                       filterArgument(dropArguments(body, 1, int.class), 0, MH_decrement}; // v = body(i-1, v)
      *     return loop(indexVar, loopLimit, bodyClause);
@@ -4619,12 +4620,12 @@ assertEquals("boojum", (String) catTrace.invokeExact("boo", "jum"));
         MethodHandle actualBody = body == null ? dropArguments(defaultResultHandle, 0, int.class) : body;
         MethodHandle returnVar = dropArguments(defaultResultHandle, 0, int.class, int.class);
         MethodHandle actualEnd = end == null ? constant(int.class, 0) : end;
+        MethodHandle decr = MethodHandleImpl.getConstantHandle(MethodHandleImpl.MH_decrementCounter);
         MethodHandle[] indexVar = {start, MethodHandleImpl.getConstantHandle(MethodHandleImpl.MH_countedLoopStep)};
         MethodHandle[] loopLimit = {actualEnd, null,
-                MethodHandleImpl.getConstantHandle(MethodHandleImpl.MH_countedLoopPred), returnVar};
+                filterArgument(MethodHandleImpl.getConstantHandle(MethodHandleImpl.MH_countedLoopPred), 0, decr),
-        MethodHandle[] bodyClause = {actualInit,
+                returnVar};
-                filterArgument(dropArguments(actualBody, 1, int.class), 0,
+        MethodHandle[] bodyClause = {actualInit, filterArgument(dropArguments(actualBody, 1, int.class), 0, decr)};
-                        MethodHandleImpl.getConstantHandle(MethodHandleImpl.MH_decrementCounter))};
         return loop(indexVar, loopLimit, bodyClause);
     }
 

jdk/test/java/lang/invoke/CountedLoopIterationCountsTest.java

@@ -0,0 +1,90 @@
+/*
+ * Copyright (c) 2016, 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 8164102
+ * @run main/othervm -ea -esa test.java.lang.invoke.CountedLoopIterationCountsTest
+ */
+
+package test.java.lang.invoke;
+
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.MethodType;
+
+public class CountedLoopIterationCountsTest {
+
+    public static void main(String[] args) throws Throwable {
+        run(1, -10, 0);
+        run(1, 0, 0);
+        run(Integer.MAX_VALUE - 1, Integer.MIN_VALUE + 10, 0);
+        run(Integer.MIN_VALUE, Integer.MIN_VALUE + 4, 4);
+        run(Integer.MAX_VALUE - 2, Integer.MAX_VALUE - 1, 1);
+        run(Integer.MAX_VALUE - 1, 0, 0);
+        run(Integer.MAX_VALUE - 1, 10, 0);
+        run(Integer.MAX_VALUE - 1, -10, 0);
+        run(Integer.MAX_VALUE, Integer.MIN_VALUE + 10, 0);
+        run(Integer.MAX_VALUE - 1, Integer.MAX_VALUE, 1);
+        run(Integer.MAX_VALUE, Integer.MAX_VALUE, 0);
+
+        if (failed) {
+            throw new AssertionError("one or more tests failed");
+        }
+    }
+
+    static boolean failed = false;
+
+    private static void run(int start, int end, int expectedIterations) throws Throwable {
+        System.out.println("run from " + start + " to " + end);
+        MethodHandle loop = MethodHandles.countedLoop(
+                MethodHandles.constant(int.class, start), // iterate from given start (inclusive) ...
+                MethodHandles.constant(int.class, end),   // ... to given end (exclusive)
+                MH_m1,                                    // initialise loop variable to -1
+                MH_step);                                 // increment loop counter by one in each iteration
+        // The loop variable's value, and hence the loop result, will be "number of iterations" minus one.
+        int r = (int) loop.invoke();
+        if (r + 1 != expectedIterations) {
+            System.out.println("expected " + expectedIterations + " iterations, but got " + r);
+            failed = true;
+        }
+    }
+
+    static int step(int counter, int stepCount) {
+        return stepCount + 1;
+    }
+
+    static final MethodHandle MH_m1;
+    static final MethodHandle MH_step;
+    static {
+        try {
+            MH_m1 = MethodHandles.constant(int.class, -1);
+            MH_step = MethodHandles.lookup().findStatic(CountedLoopIterationCountsTest.class, "step",
+                    MethodType.methodType(int.class, int.class, int.class));
+        } catch (Throwable t) {
+            throw new ExceptionInInitializerError(t);
+        }
+    }
+
+}