6675699: need comprehensive fix for unconstrained ConvI2L with narrowed type

Summary: Emit CastII to make narrow ConvI2L dependent on the corresponding range check.
Reviewed-by: kvn, roland

1 files changed, 100 insertions, 0 deletions

diff --git a/test/compiler/loopopts/TestLoopPeeling.java b/test/compiler/loopopts/TestLoopPeeling.java
new file mode 100644
index 000000000..d2d2e3d78
--- /dev/null
+++ b/test/compiler/loopopts/TestLoopPeeling.java
@@ -0,0 +1,100 @@
+/*
+ * 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.
+ *
+ * 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 8078262
+ * @summary Tests correct dominator information after loop peeling.
+ * @run main/othervm -Xcomp -XX:CompileCommand=compileonly,TestLoopPeeling::test* TestLoopPeeling
+ */
+public class TestLoopPeeling {
+
+    public int[] array = new int[100];
+
+    public static void main(String args[]) {
+        TestLoopPeeling test = new TestLoopPeeling();
+        try {
+            test.testArrayAccess(0, 1);
+            test.testArrayAllocation(0, 1);
+        } catch (Exception e) {
+            // Ignore exceptions
+        }
+    }
+
+    public void testArrayAccess(int index, int inc) {
+        int storeIndex = -1;
+
+        for (; index < 10; index += inc) {
+            // This loop invariant check triggers loop peeling because it can
+            // be moved out of the loop (see 'IdealLoopTree::policy_peeling').
+            if (inc == 42) return;
+
+            // This loop variant usage of LShiftL( ConvI2L( Phi(storeIndex) ) )
+            // prevents the split if optimization that would otherwise clone the
+            // LShiftL and ConvI2L nodes and assign them to their corresponding array
+            // address computation (see 'PhaseIdealLoop::split_if_with_blocks_post').
+            if (storeIndex > 0 && array[storeIndex] == 42) return;
+
+            if (index == 42) {
+                // This store and the corresponding range check are moved out of the
+                // loop and both used after old loop and the peeled iteration exit.
+                // For the peeled iteration, storeIndex is always -1 and the ConvI2L
+                // is replaced by TOP. However, the range check is not folded because
+                // we don't do the split if optimization in PhaseIdealLoop2.
+                // As a result, we have a (dead) control path from the peeled iteration
+                // to the StoreI but the data path is removed.
+                array[storeIndex] = 1;
+                return;
+            }
+
+            storeIndex++;
+        }
+    }
+
+    public byte[] testArrayAllocation(int index, int inc) {
+        int allocationCount = -1;
+        byte[] result;
+
+        for (; index < 10; index += inc) {
+            // This loop invariant check triggers loop peeling because it can
+            // be moved out of the loop (see 'IdealLoopTree::policy_peeling').
+            if (inc == 42) return null;
+
+            if (index == 42) {
+                // This allocation and the corresponding size check are moved out of the
+                // loop and both used after old loop and the peeled iteration exit.
+                // For the peeled iteration, allocationCount is always -1 and the ConvI2L
+                // is replaced by TOP. However, the size check is not folded because
+                // we don't do the split if optimization in PhaseIdealLoop2.
+                // As a result, we have a (dead) control path from the peeled iteration
+                // to the allocation but the data path is removed.
+                result = new byte[allocationCount];
+                return result;
+            }
+
+            allocationCount++;
+        }
+        return null;
+    }
+}
+