[mpich-discuss] Mpif90 bug report

Jonathan Ravens j.ravens.nz at gmail.com
Thu May 16 21:06:11 CDT 2019

Dear MPIf90 maintainers,

I appear to have found a bug with mpif90, running under Centos 7.
Essentially any assignment to a byte variable gives a warning or an error.
The errors are fatal, and the warnings are too numerous to ignore (I'm
getting one warning for each byte that is initialised in a DATA statement,
so that can be many thousands of warnings).  We have used code like this
since 1982 without any problems.

When mpif90 is used to compile a simple Fortran source with the
-fno-range-check option, any byte assignment in code or data statement will
give a warning, eg :

*mpif90_bug_report.f:30.13:            b1 = 6                 1    Warning:
Possible change of value in conversion from INTEGER(4) to INTEGER(1) at (1)*

This only happens with 'mpif90 -c -fno-range-check'; there is no warning
when using gfortran. However, without  -fno-range-check, we get other,
fatal, errors, so that's even worse :

* mpif90_bug_report.f:28.24:            byte b2 /  '89'X/

*   Error: Arithmetic overflow converting INTEGER(16) to INTEGER(1) at (1).
This check can be disabled with the option -fno-range-check *
I've attached a simple program to replicate the problem (mpif90_bug_report.f)

The environment details are :

> more /etc/redhat-release
CentOS Linux release 7.6.1810 (Core)

> uname -a
Linux ...  3.10.0-957.5.1.el7.x86_64 #1 SMP Fri Feb 1 14:54:57 UTC 2019
x86_64 x86_64 x86_64 GNU/Linux

> mpif90 -v
mpif90 for MPICH version 3.0.4
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-gnu-unique-object
--enable-linker-build-id --with-linker-hash-style=gnu
--enable-plugin --enable-initfini-array --disable-libgcj
--enable-gnu-indirect-function --with-tune=generic --with-arch_32=x86-64
Thread model: posix
gcc version 4.8.5 20150623 (Red Hat 4.8.5-36) (GCC)

Please don't hestitate to let me know if any further details are needed.

Many thanks,
Jonathan Ravens
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