| /* |
| * Copyright (c) 2017, 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 8177095 |
| * @summary Tests correct dominator information after loop peeling. |
| * |
| * @run main/othervm -Xcomp |
| * -XX:CompileCommand=compileonly,compiler.loopopts.TestLoopPeeling::test* |
| * compiler.loopopts.TestLoopPeeling |
| */ |
| |
| package compiler.loopopts; |
| |
| public class TestLoopPeeling { |
| |
| public int[] array = new int[100]; |
| |
| public static void main(String args[]) { |
| TestLoopPeeling test = new TestLoopPeeling(); |
| try { |
| test.testArrayAccess1(0, 1); |
| test.testArrayAccess2(0); |
| test.testArrayAccess3(0, false); |
| test.testArrayAllocation(0, 1); |
| } catch (Exception e) { |
| // Ignore exceptions |
| } |
| } |
| |
| public void testArrayAccess1(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 main 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 int testArrayAccess2(int index) { |
| // Load1 and the corresponding range check are moved out of the loop |
| // and both are used after the main loop and the peeled iteration exit. |
| // For the peeled iteration, storeIndex is always Integer.MIN_VALUE and |
| // for the main loop it is 0. Hence, the merging phi has type int:<=0. |
| // Load1 reads the array at index ConvI2L(CastII(AddI(storeIndex, -1))) |
| // where the CastII is range check dependent and has type int:>=0. |
| // The CastII gets pushed through the AddI and its type is changed to int:>=1 |
| // which does not overlap with the input type of storeIndex (int:<=0). |
| // The CastII is replaced by TOP causing a cascade of other eliminations. |
| // Since the control path through the range check CmpU(AddI(storeIndex, -1)) |
| // is not eliminated, the graph is in a corrupted state. We fail once we merge |
| // with the result of Load2 because we get data from a non-dominating region. |
| int storeIndex = Integer.MIN_VALUE; |
| for (; index < 10; ++index) { |
| if (index == 42) { |
| return array[storeIndex-1]; // Load1 |
| } |
| storeIndex = 0; |
| } |
| return array[42]; // Load2 |
| } |
| |
| public int testArrayAccess3(int index, boolean b) { |
| // Same as testArrayAccess2 but manifests as crash in register allocator. |
| int storeIndex = Integer.MIN_VALUE; |
| for (; index < 10; ++index) { |
| if (b) { |
| return 0; |
| } |
| if (index == 42) { |
| return array[storeIndex-1]; // Load1 |
| } |
| storeIndex = 0; |
| } |
| return array[42]; // Load2 |
| } |
| |
| 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 main 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; |
| } |
| } |
| |