ISNAN bug in gfortran 4.3?

[Matt Fago <fago at earthlink dot net>]

I have a large (unfortunately proprietary) F95/C code that was experiencing
some obvious memory corruption (verified by valgrind) that was fixed by 
commenting out a few calls in a loop to ISNAN of the form:
   
   DOUBLE PRECISION K(200)
   INTEGER I
   IF (ISNAN(K(I))) THEN   ! always false with test case

I did see that ISNAN is documented as taking REALs, but converting using 
REAL() did not fix the issue (nor did using REAL temporaries).

The issue seems to go away with a manual bootstrap of gcc 4.4.0.

Does this sound familiar to anyone? Was there a known bug with ISNAN in
gfortran 4.3? I didn't have any luck searching through the lists or bugzilla.


Thank you,
Matt



This was using:
gfortran -v
Using built-in specs.
Target: x86_64-redhat-linux
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-bootstrap --enable-shared --enable-threads=posix --enable-checking=release --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-languages=c,c++,objc,obj-c++,java,fortran,ada --enable-java-awt=gtk --disable-dssi --enable-plugin --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-1.5.0.0/jre --enable-libgcj-multifile --enable-java-maintainer-mode --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --disable-libjava-multilib --with-cpu=generic --build=x86_64-redhat-linux
Thread model: posix
gcc version 4.3.0 20080428 (Red Hat 4.3.0-8) (GCC)


[This is the latest gcc on Fedora 9]