gcc + gfotran 10 issue with cloverleaf + mpi

[cyrush]

hit this using ubunutu 20.10 while testing gcc 10:

/ascent/src/examples/proxies/cloverleaf3d-ref/clover.F90:4192:21:

 4192 |   CALL MPI_ALLREDUCE(value,maximum,1,MPI_DOUBLE_PRECISION,MPI_MAX,MPI_COMM_WORLD,err)
      |                     1
......
 4226 |   CALL MPI_ALLREDUCE(error,maximum,1,MPI_INTEGER,MPI_MAX,MPI_COMM_WORLD,err)
      |                     2
Error: Type mismatch between actual argument at (1) and actual argument at (2) (REAL(8)/INTEGER(4)).
/ascent/src/examples/proxies/cloverleaf3d-ref/clover.F90:4174:21:

 4174 |   CALL MPI_ALLREDUCE(value,minimum,1,MPI_DOUBLE_PRECISION,MPI_MIN,MPI_COMM_WORLD,err)
      |                     1
......
 4226 |   CALL MPI_ALLREDUCE(error,maximum,1,MPI_INTEGER,MPI_MAX,MPI_COMM_WORLD,err)
      |                     2
Error: Type mismatch between actual argument at (1) and actual argument at (2) (REAL(8)/INTEGER(4)).

there isn't an obvious mismatch unless there is something strange with the MPI API

similar discussion:

Unidata/netcdf-fortran#212

[cyrush]

while I would like to understand what is going on here - it does seem most folks are opting to mute gcc's complaints:

GlobalArrays/ga#157 (comment)

[cyrush]

Newer mpich add these flags as part of their -show report:

f95 -O2 -fdebug-prefix-map=/build/mpich-lMcyOH/mpich-3.4~a2+really3.3.2=. -fstack-protector-strong -fallow-invalid-boz 
-fallow-argument-mismatch -Wl,-Bsymbolic-functions -Wl,-z,relro -I/usr/include/x86_64-linux-gnu/mpich -I/usr/include/x86_64-linux-gnu/mpich -L/usr/lib/x86_64-linux-gnu -lmpichfort -lmpich

BLT fuses all of these, so we will end up with warnings from the C++ compiler about how these are fortran flags :-(

cc1plus: warning: command-line option '-fallow-invalid-boz' is valid for Fortran but not for C++
cc1plus: warning: command-line option '-fallow-argument-mismatch' is valid for Fortran but not for C++

[jfavre]

I have two systems (Ubuntu with cmake 3.18.4 and a Cray with cmake 3.21.1). The fix provided does not work because of the double quotes surrounding the two compile flags options.

I was able to restart the compilation in both cases, by removing the double quotes, i.e. replacing
"-DUSE_MPIF -fallow-invalid-boz -fallow-argument-mismatch" by
-DUSE_MPIF -fallow-invalid-boz -fallow-argument-mismatch
on the command line.

in both cases, compilation terminated successfully.

[cyrush]

@jfavre thanks I'll take a look again!