Complicated logic for reduced gcc_10 combinations

mpcdf_common.py

@@ -200,6 +200,15 @@ def valid_mpi(compiler, mpi):
         return mpi == compiler_parallel_studio[compiler]["impi"]
     if compiler.startswith("pgi"):
         return valid_pgi_mpi(compiler, mpi)
+    if compiler.startswith("gcc") and mpi.startswith("impi"):
+        gcc_version = int(compiler[len("gcc_"):])
+        impi_major_version, impi_minor_version = map(int, mpi[len("impi_"):].split("_"))
+        if gcc_version >= 10:
+            # gcc_10 only with modern Intel MPI
+            return impi_major_version > 2019 or \
+                (impi_major_version == 2019 and impi_minor_version >= 7)
+        else:
+            return True
     else:
         return True