[Bug classpath/33206] New: Long overflow in BigInteger.java

[johnx at dodgit dot com]

Bug.java:
---
import java.math.BigInteger;

class Bug {
  public static void main(String[] args) {
    BigInteger test = new
BigInteger("340282366920938463463374607431768211457");
    System.out.println(test.isProbablePrime(80));
  }
}
---

Problem:

BigInteger.java:1316:
  BigInteger m = pMinus1.divide(valueOf(2L << b - 1));

But b = 128, so 2 << 127 does not fit in a long.

Solution:
  BigInteger m = pMinus1.divide(new BigInteger("2").pow(b - 1));


-- 
           Summary: Long overflow in BigInteger.java
           Product: classpath
           Version: unspecified
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: classpath
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: johnx at dodgit dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33206