The configure script and configure.ac check for compiler:

case "$CC" in *icc*) # ICC needs -fp-model strict or floats behave badly CFLAGS_NODIST="$CFLAGS_NODIST -fp-model strict" ;; *xlc*) CFLAGS_NODIST="$CFLAGS_NODIST -qalias=noansi -qmaxmem=-1" ;; esac

The MPI GCC compiler: mpicc is qualified as the intel compiler, because of the 'icc' in the name, and applies the fp-model strict option to the arguments, which is invalid syntax for GCC, causing multiple compile time errors with recent GCC versions:

gcc: error: unrecognized command-line option ‘-fp-model’; did you mean ‘-fipa-modref’?

By first filtering out the mpicc compiler case, this mistake is prevented:

case "$CC" in *mpicc*) CFLAGS_NODIST="$CFLAGS_NODIST" ;; *icc*) # ICC needs -fp-model strict or floats behave badly CFLAGS_NODIST="$CFLAGS_NODIST -fp-model strict" ;; *xlc*) CFLAGS_NODIST="$CFLAGS_NODIST -qalias=noansi -qmaxmem=-1" ;; esac

(Now that I have this created, I can no doubt use its issue number to get the pull request with this fix through the pipeline)

Linked PRs

• gh-106962: Detect mpicc in configure.ac #106961
• [3.12] gh-106962: Detect mpicc in configure.ac (GH-106961) #107081