Hi, [This bug was initially submitted to the Debian BTS at http://bugs.debian.org/466948 -- at the request of Debian's gcc maintainer, I am also sending it here]
There is apparently a miscompilation of CERNLIB code in the "kernlib" library on ia64 with gfortran-4.3 at optimization level -O2 or higher. (Oddly, compiling with -O2 -funroll-loops does not expose the problem, which is why I didn't notice it earlier.) I've verified that this problem occurs on ia64 with gfortran-4.3 versions 4.3-20080202-1, 4.3-20080219-1 and 4.3.0. For the most recent trial: (sid)[EMAIL PROTECTED]:~$ gfortran-4.3 -v Using built-in specs. Target: ia64-linux-gnu Configured with: ../src/configure linux gnu Thread model: posix gcc version 4.3.1 20080309 (prerelease) (Debian 4.3.0-1) Please see the complete test case I've provided at http://people.debian.org/~kmccarty/tlsc-test-case.tar.gz [Note, the files libkernlib.a and libkerngent.a in the tarball were compiled on ia64 from CERNLIB source code, which is GPL; it is available from the Debian source package of "cernlib" version 2006.dfsg.2-10] [Note 2, I have updated this test case tarball to the gfortran version noted above since I originally submitted this bug to the Debian BTS.] The file tlsc.F in the test case is where the optimization bug happens. I saved files tlsc.f, tlsc.s and tlsc.o into subdirectories of the test case for three different combinations of compile flags: -O2 (causes miscompiled code) in obj-fail subdir -O0 (seems fine) -O2 -funroll-loops (seems fine) both in obj-success subdir. Also the output of the test case, saved as output.txt in each subdir. You can regenerate all of these files with these three combinations of compiler flags quickly with "make output". The presence or absence of -fno-automatic on the gfortran command line (I omitted it in all three cases) appears to make no difference. best regards, Kevin McCarty -- Summary: Miscompiled code with -O2 (but not with -O2 -funroll- loops) on ia64 Product: gcc Version: 4.3.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: fortran AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: kmccarty at debian dot org GCC build triplet: ia64-linux-gnu GCC host triplet: ia64-linux-gnu GCC target triplet: ia64-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35659
