# HG changeset patch # User vlivanov # Date 1350931470 25200 # Node ID 67f4c477c9ab9004d219a34969a025471e1e6671 # Parent aaeb9add1ab3e571c0538b5cafc7e1ba5ff3d42b 8000805: JMM issue: short loads are non-atomic Summary: perform transforms during IGVN phase when Load has a single user. Reviewed-by: jrose, kvn, twisti diff -r aaeb9add1ab3 -r 67f4c477c9ab src/share/vm/opto/mulnode.cpp --- a/src/share/vm/opto/mulnode.cpp Fri Oct 19 14:21:09 2012 -0400 +++ b/src/share/vm/opto/mulnode.cpp Mon Oct 22 11:44:30 2012 -0700 @@ -479,24 +479,27 @@ return new (phase->C) AndINode(load,phase->intcon(mask&0xFFFF)); // Masking bits off of a Short? Loading a Character does some masking - if (lop == Op_LoadS && (mask & 0xFFFF0000) == 0 ) { - Node *ldus = new (phase->C) LoadUSNode(load->in(MemNode::Control), - load->in(MemNode::Memory), - load->in(MemNode::Address), - load->adr_type()); - ldus = phase->transform(ldus); - return new (phase->C) AndINode(ldus, phase->intcon(mask & 0xFFFF)); - } + if (can_reshape && + load->outcnt() == 1 && load->unique_out() == this) { + if (lop == Op_LoadS && (mask & 0xFFFF0000) == 0 ) { + Node *ldus = new (phase->C) LoadUSNode(load->in(MemNode::Control), + load->in(MemNode::Memory), + load->in(MemNode::Address), + load->adr_type()); + ldus = phase->transform(ldus); + return new (phase->C) AndINode(ldus, phase->intcon(mask & 0xFFFF)); + } - // Masking sign bits off of a Byte? Do an unsigned byte load plus - // an and. - if (lop == Op_LoadB && (mask & 0xFFFFFF00) == 0) { - Node* ldub = new (phase->C) LoadUBNode(load->in(MemNode::Control), - load->in(MemNode::Memory), - load->in(MemNode::Address), - load->adr_type()); - ldub = phase->transform(ldub); - return new (phase->C) AndINode(ldub, phase->intcon(mask)); + // Masking sign bits off of a Byte? Do an unsigned byte load plus + // an and. + if (lop == Op_LoadB && (mask & 0xFFFFFF00) == 0) { + Node* ldub = new (phase->C) LoadUBNode(load->in(MemNode::Control), + load->in(MemNode::Memory), + load->in(MemNode::Address), + load->adr_type()); + ldub = phase->transform(ldub); + return new (phase->C) AndINode(ldub, phase->intcon(mask)); + } } // Masking off sign bits? Dont make them! @@ -923,7 +926,9 @@ set_req(2, phase->intcon(0)); return this; } - else if( ld->Opcode() == Op_LoadUS ) + else if( can_reshape && + ld->Opcode() == Op_LoadUS && + ld->outcnt() == 1 && ld->unique_out() == shl) // Replace zero-extension-load with sign-extension-load return new (phase->C) LoadSNode( ld->in(MemNode::Control), ld->in(MemNode::Memory), diff -r aaeb9add1ab3 -r 67f4c477c9ab test/compiler/8000805/Test8000805.java --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/test/compiler/8000805/Test8000805.java Mon Oct 22 11:44:30 2012 -0700 @@ -0,0 +1,85 @@ +/* + * Copyright (c) 2012, 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 8000805 + * @summary JMM issue: short loads are non-atomic + * + * @run main/othervm -server -XX:-TieredCompilation -Xcomp -XX:+PrintCompilation -XX:CompileOnly=Test8000805.loadS2LmaskFF,Test8000805.loadS2Lmask16,Test8000805.loadS2Lmask13,Test8000805.loadUS_signExt,Test8000805.loadB2L_mask8 Test8000805 + */ + +public class Test8000805 { + static long loadS2LmaskFF (short[] sa) { return sa[0] & 0xFF; } + static long loadS2LmaskFF_1 (short[] sa) { return sa[0] & 0xFF; } + + static long loadS2Lmask16 (short[] sa) { return sa[0] & 0xFFFE; } + static long loadS2Lmask16_1 (short[] sa) { return sa[0] & 0xFFFE; } + + static long loadS2Lmask13 (short[] sa) { return sa[0] & 0x0FFF; } + static long loadS2Lmask13_1 (short[] sa) { return sa[0] & 0x0FFF; } + + static int loadUS_signExt (char[] ca) { return (ca[0] << 16) >> 16; } + static int loadUS_signExt_1 (char[] ca) { return (ca[0] << 16) >> 16; } + + static long loadB2L_mask8 (byte[] ba) { return ba[0] & 0x55; } + static long loadB2L_mask8_1 (byte[] ba) { return ba[0] & 0x55; } + + public static void main(String[] args) { + for (int i = Byte.MIN_VALUE; i < Byte.MAX_VALUE; i++) { + byte[] ba = new byte[] { (byte) i}; + + { long v1 = loadB2L_mask8(ba); + long v2 = loadB2L_mask8_1(ba); + if (v1 != v2) + throw new InternalError(String.format("loadB2L_mask8 failed: %x != %x", v1, v2)); } + } + + for (int i = Short.MIN_VALUE; i < Short.MAX_VALUE; i++) { + short[] sa = new short[] { (short)i }; + char[] ca = new char[] { (char)i }; + + { long v1 = loadS2LmaskFF(sa); + long v2 = loadS2LmaskFF_1(sa); + if (v1 != v2) + throw new InternalError(String.format("loadS2LmaskFF failed: %x != %x", v1, v2)); } + + { long v1 = loadS2Lmask16(sa); + long v2 = loadS2Lmask16_1(sa); + if (v1 != v2) + throw new InternalError(String.format("loadS2Lmask16 failed: %x != %x", v1, v2)); } + + { long v1 = loadS2Lmask13(sa); + long v2 = loadS2Lmask13_1(sa); + if (v1 != v2) + throw new InternalError(String.format("loadS2Lmask13 failed: %x != %x", v1, v2)); } + + { int v1 = loadUS_signExt(ca); + int v2 = loadUS_signExt_1(ca); + if (v1 != v2) + throw new InternalError(String.format("loadUS_signExt failed: %x != %x", v1, v2)); } + } + + System.out.println("TEST PASSED."); + } +}