6795362: 32bit server compiler leads to wrong results on solaris-x86
Summary: The C2 compiler leads to wrong results on solaris-i486 (32-bit) for a testcase given in the CR.
Reviewed-by: never, rasbold
--- a/hotspot/src/share/vm/opto/mulnode.cpp Mon Jan 26 16:22:12 2009 +0100
+++ b/hotspot/src/share/vm/opto/mulnode.cpp Tue Feb 03 01:39:12 2009 -0800
@@ -1,5 +1,5 @@
/*
- * Copyright 1997-2008 Sun Microsystems, Inc. All Rights Reserved.
+ * Copyright 1997-2009 Sun Microsystems, Inc. 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
@@ -449,9 +449,10 @@
// needed either.
if( lop == Op_URShiftI ) {
const TypeInt *t12 = phase->type( load->in(2) )->isa_int();
- if( t12 && t12->is_con() ) {
- int shift_con = t12->get_con();
- int mask = max_juint >> shift_con;
+ if( t12 && t12->is_con() ) { // Shift is by a constant
+ int shift = t12->get_con();
+ shift &= BitsPerJavaInteger - 1; // semantics of Java shifts
+ int mask = max_juint >> shift;
if( (mask&con) == mask ) // If AND is useless, skip it
return load;
}
@@ -579,9 +580,10 @@
// needed either.
if( lop == Op_URShiftL ) {
const TypeInt *t12 = phase->type( usr->in(2) )->isa_int();
- if( t12 && t12->is_con() ) {
- int shift_con = t12->get_con();
- jlong mask = max_julong >> shift_con;
+ if( t12 && t12->is_con() ) { // Shift is by a constant
+ int shift = t12->get_con();
+ shift &= BitsPerJavaLong - 1; // semantics of Java shifts
+ jlong mask = max_julong >> shift;
if( (mask&con) == mask ) // If AND is useless, skip it
return usr;
}
@@ -605,8 +607,8 @@
const TypeInt *t12 = phase->type(rsh->in(2))->isa_int();
if( t12 && t12->is_con() ) { // Shift is by a constant
int shift = t12->get_con();
- shift &= (BitsPerJavaInteger*2)-1; // semantics of Java shifts
- const jlong sign_bits_mask = ~(((jlong)CONST64(1) << (jlong)(BitsPerJavaInteger*2 - shift)) -1);
+ shift &= BitsPerJavaLong - 1; // semantics of Java shifts
+ const jlong sign_bits_mask = ~(((jlong)CONST64(1) << (jlong)(BitsPerJavaLong - shift)) -1);
// If the AND'ing of the 2 masks has no bits, then only original shifted
// bits survive. NO sign-extension bits survive the maskings.
if( (sign_bits_mask & mask) == 0 ) {
@@ -786,7 +788,7 @@
// Check for ((x & ((CONST64(1)<<(64-c0))-1)) << c0) which ANDs off high bits
// before shifting them away.
- const jlong bits_mask = ((jlong)CONST64(1) << (jlong)(BitsPerJavaInteger*2 - con)) - CONST64(1);
+ const jlong bits_mask = ((jlong)CONST64(1) << (jlong)(BitsPerJavaLong - con)) - CONST64(1);
if( add1_op == Op_AndL &&
phase->type(add1->in(2)) == TypeLong::make( bits_mask ) )
return new (phase->C, 3) LShiftLNode( add1->in(1), in(2) );
@@ -820,7 +822,7 @@
return TypeLong::LONG;
uint shift = r2->get_con();
- shift &= (BitsPerJavaInteger*2)-1; // semantics of Java shifts
+ shift &= BitsPerJavaLong - 1; // semantics of Java shifts
// Shift by a multiple of 64 does nothing:
if (shift == 0) return t1;
@@ -1235,7 +1237,7 @@
if ( con == 0 ) return NULL; // let Identity() handle a 0 shift count
// note: mask computation below does not work for 0 shift count
// We'll be wanting the right-shift amount as a mask of that many bits
- const jlong mask = (((jlong)CONST64(1) << (jlong)(BitsPerJavaInteger*2 - con)) -1);
+ const jlong mask = (((jlong)CONST64(1) << (jlong)(BitsPerJavaLong - con)) -1);
// Check for ((x << z) + Y) >>> z. Replace with x + con>>>z
// The idiom for rounding to a power of 2 is "(Q+(2^z-1)) >>> z".
@@ -1302,7 +1304,7 @@
if (r2->is_con()) {
uint shift = r2->get_con();
- shift &= (2*BitsPerJavaInteger)-1; // semantics of Java shifts
+ shift &= BitsPerJavaLong - 1; // semantics of Java shifts
// Shift by a multiple of 64 does nothing:
if (shift == 0) return t1;
// Calculate reasonably aggressive bounds for the result.
@@ -1325,7 +1327,7 @@
const TypeLong* tl = TypeLong::make(lo, hi, MAX2(r1->_widen,r2->_widen));
#ifdef ASSERT
// Make sure we get the sign-capture idiom correct.
- if (shift == (2*BitsPerJavaInteger)-1) {
+ if (shift == BitsPerJavaLong - 1) {
if (r1->_lo >= 0) assert(tl == TypeLong::ZERO, ">>>63 of + is 0");
if (r1->_hi < 0) assert(tl == TypeLong::ONE, ">>>63 of - is +1");
}
--- a/hotspot/src/share/vm/utilities/globalDefinitions.hpp Mon Jan 26 16:22:12 2009 +0100
+++ b/hotspot/src/share/vm/utilities/globalDefinitions.hpp Tue Feb 03 01:39:12 2009 -0800
@@ -1,5 +1,5 @@
/*
- * Copyright 1997-2008 Sun Microsystems, Inc. All Rights Reserved.
+ * Copyright 1997-2009 Sun Microsystems, Inc. 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
@@ -74,6 +74,7 @@
extern int BitsPerHeapOop;
const int BitsPerJavaInteger = 32;
+const int BitsPerJavaLong = 64;
const int BitsPerSize_t = size_tSize * BitsPerByte;
// Size of a char[] needed to represent a jint as a string in decimal.
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/test/compiler/6795362/Test6795362.java Tue Feb 03 01:39:12 2009 -0800
@@ -0,0 +1,48 @@
+/*
+ * Copyright 2009 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+/**
+ * @test
+ * @bug 6795362
+ * @summary 32bit server compiler leads to wrong results on solaris-x86
+ *
+ * @run main/othervm -Xcomp -XX:CompileOnly=Test6795362.sub Test6795362
+ */
+
+public class Test6795362 {
+ public static void main(String[] args)
+ {
+ sub();
+
+ if (var_bad != 0)
+ throw new InternalError(var_bad + " != 0");
+ }
+
+ static long var_bad = -1L;
+
+ static void sub()
+ {
+ var_bad >>= 65;
+ var_bad /= 65;
+ }
+}