libgcj/4616: Floating Point Math class problem on Tru64 Alpha v 5.1

Sat Jan 5 12:54:00 GMT 2002

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=4616
The following was submitted by ake@purdue.edu, but ended up in the wrong
PR.
Do not change the format of the subject line when CC:'ing messages to
GNATS.
===============================================================
 Hello, These are the results of the C program:
 Argument arg is 3.780800e+02
 Argument y is 1.577821e+164
 Argument x is 1.797693e+308
 Argument result is 1.755384e-144
 BUT if x=y=overflow, this is the result:
 Argument arg is 9.000000e+02
 Argument y is 1.797693e+308
 Argument x is 1.797693e+308
 Floating point exception (core dumped)
 More testing on Alpha and Java showed this:
 If arg >=261 the program is STALLED. No floating core dump, and it
 doesn't execute the print of "x":
 Argument arg is 261.0 Argument y is 2.2431575451828986E113
 Regards
 On 2001年10月19日, Andrew Haley wrote:
 > ake@purdue.edu writes:
 > > >Category: libgcj
 > > >Synopsis: Floating Point Math class problem on Tru64 Alpha
v 5.1
 > > >Confidential: no
 > > >Severity: serious
 > > >Priority: medium
 > > >Class: sw-bug
 > > >Submitter-Id: net
 > > >Originator: Antonio Ake
 > > >Release: 3.0.2 prerelease
 > > >Environment:
 > > TRu64 Unix v 5.1
 > > >Description:
 > > his is the part of the code executing:
 > > public static double d1f (double arg) {
 > > double y,x;
 > >
 > > System.out.print("Argument arg is " + arg + " ");
 > > y= Math.exp(arg);
 > > System.out.print("Argument y is " + y + " ");
 > > x=Math.pow((y+1.0),2.0);
 > > System.out.print("Argument x is " + x + "\n");
 > > return ( (2.0 * y)/x );
 > > }
 > > The problem is when x is infinity.
 > > Argument arg is 378.0812928461101
 > > Var y is 1.5798621479294393E164
 > > Var x is Infinity
 > > Floating point exception (core dumped)
 > > I tested on Linux x/86 and it is working, the problem is on Tru64
Unix
 >
 > Fascianting. It looks as though floating-point exceptions trigger a
 > signal on this system. I've never come across a system which does
 > this before.
 >
 > Can you please write a trivial C program that does the same thing and
 > see if it also results in a Floating point exception?
 >
 > Thanks,
 > Andrew.
 >