--- old/test/compiler/loopopts/TestLoopPeeling.java 2017-03-24 07:41:09.159908512 +0100 +++ new/test/compiler/loopopts/TestLoopPeeling.java 2017-03-24 07:41:09.087908516 +0100 @@ -1,5 +1,5 @@ /* - * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved. + * 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 @@ -23,10 +23,16 @@ /* * @test - * @bug 8078262 + * @bug 8078262 8177095 * @summary Tests correct dominator information after loop peeling. - * @run main/othervm -Xcomp -XX:CompileCommand=compileonly,TestLoopPeeling::test* TestLoopPeeling + * + * @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]; @@ -34,14 +40,16 @@ public static void main(String args[]) { TestLoopPeeling test = new TestLoopPeeling(); try { - test.testArrayAccess(0, 1); + test.testArrayAccess1(0, 1); + test.testArrayAccess2(0); + test.testArrayAccess3(0, false); test.testArrayAllocation(0, 1); } catch (Exception e) { // Ignore exceptions } } - public void testArrayAccess(int index, int inc) { + public void testArrayAccess1(int index, int inc) { int storeIndex = -1; for (; index < 10; index += inc) { @@ -57,7 +65,7 @@ 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. + // 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. @@ -71,6 +79,44 @@ } } + 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; @@ -82,7 +128,7 @@ 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. + // 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.