re PR libfortran/21376 (libfortran "E" output format causes FPE)

	PR libfortran/21376
	* io/write.c (output_float): Rework logic to avoid call to log10
	with argument equal to zero.

From-SVN: r100068

libgfortran/ChangeLog

+2005-05-22  Francois-Xavier Coudert  <coudert@clipper.ens.fr>
+
+	PR libfortran/21376
+	* io/write.c (output_float): Rework logic to avoid call to log10
+	with argument equal to zero.
+
 2005-05-21  Eric Botcazou  <ebotcazou@libertysurf.fr>
 
 	* configure.ac: Check for trunc and truncf in libm.

libgfortran/io/write.c

@@ -296,6 +296,7 @@ output_float (fnode *f, double value)
   int nblanks;
   int i;
   sign_t sign;
+  double abslog;
 
   ft = f->format;
   w = f->u.real.w;
@@ -320,9 +321,11 @@ output_float (fnode *f, double value)
     edigits = 2;
   else
     {
-      edigits = 1 + (int) log10 (fabs(log10 (value)));
-      if (edigits < 2)
+      abslog = fabs(log10 (value));
+      if (abslog < 100)
 	edigits = 2;
+      else
+        edigits = 1 + (int) log10 (abslog);
     }
 
   if (ft == FMT_F || ft == FMT_EN