Re: egcs-1.1.1 Release

[Gerhard Heinzel <ghh at mpq dot mpg dot de>]

On Fri, 4 Dec 1998, Jeffrey A Law wrote:

>    We are pleased to announce the release of egcs-1.1.1.
....
>    
>    egcs-1.1.1 is a minor update to the egcs-1.1 compiler to fix several
>    serious problems in egcs-1.1.

Sorry to report again failure to correctly compile the short test program
included below, when using the options

-march=i686 -O

(Complier: gcc version egcs-2.91.60 19981201 (egcs-1.1.1 release))


If this bug cannot be fixed, I propose to disable the -march=i686 option,
since producing spurious wrong code without a warning is about the worst
thing a compiler can do.

Cheers

Gerhard

#include <stdio.h>
#include <math.h>
#define SIZE 10

int
main (void)
{
  int i, j, k;
  double a[SIZE * SIZE], ainv[SIZE * SIZE];
  double diff, sum, soll, maxd;

  /* matrix addressing : a(i,j) = a[n*i+j] */

  /* Normally here 'a' is a double matrix and 'ainv' its inverse */
  /* For testing, set 'a' and 'ainv' as unity matrices */
  for (i = 0; i < SIZE; i++)
    for (j = 0; j < SIZE; j++)
      a[i * SIZE + j] = ainv[i * SIZE + j] = ((i == j) ? 1 : 0);

  /* compute the product a*ainv element by element and compare to
     unity matrix */

  maxd = 0;			/* maximum of difference */
  for (i = 0; i < SIZE; i++)
    for (j = 0; j < SIZE; j++)
      /* compute element (i,j) of product */
      {
/*1*/	sum = 0;
/*2*/	soll = ((i == j) ? 1 : 0);	/* this should be the result */
	for (k = 0; k < SIZE; k++)
	  sum += a[i * SIZE + k] * ainv[k * SIZE + j];
	diff = fabs (sum - soll);	/* measure difference */
	if (diff > maxd)	/* record maximum difference */
	  maxd = diff;
      }
  printf ("maxd=%g \n", maxd);
  return 0;
}

Program should print '0' but prints 'NaN' instead.

=====================================================================
 Gerhard Heinzel                            E-mail:   ghh@mpq.mpg.de
 Max-Planck-Institut fuer Quantenoptik   Phone: +49(89)32905-268/252
 Hans-Kopfermann-Str. 1            Phone (30m Lab): +49(89)3299-3282
 D-85748 Garching                              Fax: +49(89)32905-200  
 Germany                                        http://130.183.90.63
=====================================================================