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/*
* 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.
*
* 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 8015396
* @summary double a%b returns NaN for some (a,b) (|a| < inf, |b|>0) (on Core i7 980X)
*
* @run main compiler.floatingpoint.ModNaN
*/
package compiler.floatingpoint;
public class ModNaN {
/* This bug was seen in the field for a particular version of the VM,
* but never reproduced internally, and the reason was never known,
* nor were the exact circumstances of the failure.
*/
/*
* Failed on Windows 7/Core i7 980X/1.6.0_38 (64-bit):
*
* NaNs (i.e., when it fails, this is what we expect to see):
*
* 8.98846567431158E307 % 1.295163E-318 = NaN
* (0x7FE0000000000000L % 0x0000000000040000L)
*
* 1.7976931348623157E308 % 2.59032E-318 = NaN
* (0x7FEFFFFFFFFFFFFFL % 0x000000000007FFFFL)
*
* 1.7976931348623157E308 % 1.060997895E-314 = NaN
* (0x7FEFFFFFFFFFFFFFL % 0x000000007FFFFFFFL)
*
* 1.7976931348623157E308 % 6.767486E-317 = NaN
* (0x7FEFFFFFFFFFFFFFL % 0x0000000000d10208L)
*
* 1.7976931348623157E308 % 7.528725E-318 = NaN
* (0x7FEFFFFFFFFFFFFFL % 0x0000000000174077L)
*
* These cases did not fail, even when the previous five did:
* 8.98846567431158E307 % 1.29516E-318 = 2.53E-321
* (0x7fe0000000000000L % 0x000000000003ffffL)
*
* 1.7976931348623157E308 % 2.590327E-318 = 0.0
* (0x7fefffffffffffffL % 0x0000000000080000L)
*
* 1.7976931348623157E308 % 1.060965516E-314 = 9.35818525E-315
* (0x7fefffffffffffffL % 0x000000007ffeffffL)
*
*/
static double[][] bad = new double[][] {
/*
* These hex numbers correspond to the base-10 doubles in the
* comment above; this can be checked by observing the output
* of testWithPrint.
*/
new double[] { Double.longBitsToDouble(0x7FE0000000000000L),
Double.longBitsToDouble(0x0000000000040000L) },
new double[] { Double.longBitsToDouble(0x7FEFFFFFFFFFFFFFL),
Double.longBitsToDouble(0x000000000007FFFFL) },
new double[] { Double.longBitsToDouble(0x7FEFFFFFFFFFFFFFL),
Double.longBitsToDouble(0x000000007FFFFFFFL) },
new double[] { Double.longBitsToDouble(0x7FEFFFFFFFFFFFFFL),
6.767486E-317 },
new double[] { Double.longBitsToDouble(0x7FEFFFFFFFFFFFFFL),
7.528725E-318 }, };
static double[][] good = new double[][] {
new double[] { Double.longBitsToDouble(0x7FE0000000000000L),
Double.longBitsToDouble(0x000000000003FFFFL) },
new double[] { Double.longBitsToDouble(0x7FEFFFFFFFFFFFFFL),
Double.longBitsToDouble(0x0000000000080000L) },
new double[] { Double.longBitsToDouble(0x7FEFFFFFFFFFFFFFL),
Double.longBitsToDouble(0x000000007FFEFFFFL) }, };
public static void main(String[] args) throws InterruptedException {
int N = 10000;
testWithPrint();
for (int i = 0; i < N; i++)
testStrict();
for (int i = 0; i < N; i++)
test();
Thread.sleep(1000); // pause to let the compiler work
for (int i = 0; i < 10; i++)
testStrict();
for (int i = 0; i < 10; i++)
test();
}
public strictfp static void testWithPrint() {
for (double[] ab : bad) {
double a = ab[0];
double b = ab[1];
double mod = a % b;
System.out.println("" + a + "("+toHexRep(a)+") mod " +
b + "("+toHexRep(b)+") yields " +
mod + "("+toHexRep(mod)+")");
}
for (double[] ab : good) {
double a = ab[0];
double b = ab[1];
double mod = a % b;
System.out.println("" + a + "("+toHexRep(a)+") mod " +
b + "("+toHexRep(b)+") yields " +
mod + "("+toHexRep(mod)+")");
}
}
public strictfp static void testStrict() {
for (double[] ab : bad) {
double a = ab[0];
double b = ab[1];
double mod = a % b;
check(mod);
}
for (double[] ab : good) {
double a = ab[0];
double b = ab[1];
double mod = a % b;
check(mod);
}
}
public static void test() {
for (double[] ab : bad) {
double a = ab[0];
double b = ab[1];
double mod = a % b;
check(mod);
}
for (double[] ab : good) {
double a = ab[0];
double b = ab[1];
double mod = a % b;
check(mod);
}
}
static String toHexRep(double d) {
return "0x" + Long.toHexString(Double.doubleToRawLongBits(d)) + "L";
}
static void check(double mod) {
if (Double.isNaN(mod)) {
throw new Error("Saw a NaN, fail");
}
}
}
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