提交 2d797dad 编写于 作者: T twisti

6805724: ModLNode::Ideal() generates functionally incorrect graph when divisor...

6805724: ModLNode::Ideal() generates functionally incorrect graph when divisor is any (2^k-1) constant.
Summary: C2, ModLNode::Ideal() generates functionally incorrect graph when divisor is any (2^k-1) constant.
Reviewed-by: rasbold
上级 23f32ec7
......@@ -1007,7 +1007,7 @@ Node *ModLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
// Expand mod
if( con >= 0 && con < max_jlong && is_power_of_2_long(con+1) ) {
uint k = log2_long(con); // Extract k
uint k = exact_log2_long(con+1); // Extract k
// Basic algorithm by David Detlefs. See fastmod_long.java for gory details.
// Used to help a popular random number generator which does a long-mod
......
......@@ -907,6 +907,14 @@ inline int exact_log2(intptr_t x) {
return log2_intptr(x);
}
//* the argument must be exactly a power of 2
inline int exact_log2_long(jlong x) {
#ifdef ASSERT
if (!is_power_of_2_long(x)) basic_fatal("x must be a power of 2");
#endif
return log2_long(x);
}
// returns integer round-up to the nearest multiple of s (s must be a power of two)
inline intptr_t round_to(intptr_t x, uintx s) {
......
/*
* 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 6805724
* @summary ModLNode::Ideal() generates functionally incorrect graph when divisor is any (2^k-1) constant.
*
* @run main/othervm -Xcomp -XX:CompileOnly=Test6805724.fcomp Test6805724
*/
import java.net.URLClassLoader;
public class Test6805724 implements Runnable {
// Initialize DIVISOR so that it is final in this class.
static final long DIVISOR; // 2^k-1 constant
static {
long value = 0;
try {
value = Long.decode(System.getProperty("divisor"));
} catch (Throwable t) {
// This one is required for the Class.forName() in main.
}
DIVISOR = value;
}
static long fint(long x) {
return x % DIVISOR;
}
static long fcomp(long x) {
return x % DIVISOR;
}
public void run() {
long a = 0x617981E1L;
long expected = fint(a);
long result = fcomp(a);
if (result != expected)
throw new InternalError(result + " != " + expected);
}
public static void main(String args[]) throws Exception {
Class cl = Class.forName("Test6805724");
URLClassLoader apploader = (URLClassLoader) cl.getClassLoader();
// Iterate over all 2^k-1 divisors.
for (int k = 1; k < Long.SIZE; k++) {
long divisor = (1L << k) - 1;
System.setProperty("divisor", "" + divisor);
ClassLoader loader = new URLClassLoader(apploader.getURLs(), apploader.getParent());
Class c = loader.loadClass("Test6805724");
Runnable r = (Runnable) c.newInstance();
r.run();
}
}
}
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