--- old/src/share/vm/opto/memnode.cpp 2014-10-23 22:11:38.000000000 +0400 +++ new/src/share/vm/opto/memnode.cpp 2014-10-23 22:11:38.000000000 +0400 @@ -1257,6 +1257,16 @@ result = new ConvI2LNode(phase->transform(result)); } #endif + // Boxing/unboxing can be done from signed & unsigned loads (e.g. LoadUB -> ... -> LoadB pair). + // Need to preserve unboxing load type if it is unsigned. + switch(this->Opcode()) { + case Op_LoadUB: + result = new AndINode(phase->transform(result), phase->intcon(0xFF)); + break; + case Op_LoadUS: + result = new AndINode(phase->transform(result), phase->intcon(0xFFFF)); + break; + } return result; } } --- /dev/null 2014-10-23 22:11:40.000000000 +0400 +++ new/test/compiler/EliminateAutoBox/UnsignedLoads.java 2014-10-23 22:11:39.000000000 +0400 @@ -0,0 +1,63 @@ +/* + * Copyright (c) 2014, 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 + * @library /testlibrary + * @run main/othervm -Xbatch -XX:+EliminateAutoBox + * -XX:CompileOnly=::valueOf,::byteValue,::shortValue,::testUnsignedByte,::testUnsignedShort + * UnsignedLoads + */ +import static com.oracle.java.testlibrary.Asserts.assertEQ; + +public class UnsignedLoads { + public static int testUnsignedByte() { + byte[] bytes = new byte[] {-1}; + int res = 0; + for (int i = 0; i < 100000; i++) { + for (Byte b : bytes) { + res = b & 0xff; + } + } + return res; + } + + public static int testUnsignedShort() { + int res = 0; + short[] shorts = new short[] {-1}; + for (int i = 0; i < 100000; i++) { + for (Short s : shorts) { + res = s & 0xffff; + } + } + return res; + } + + public static void main(String[] args) { + assertEQ(testUnsignedByte(), 255); + assertEQ(testUnsignedShort(), 65535); + System.out.println("TEST PASSED"); + } +}