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Argonne Leadership Computing Facility

LLVM Compilers on Polaris

This page is not about LLVM-based Cray Compiling Environment (CCE) compilers from PrgEnv-cray but about open-source LLVM compilers.

If LLVM compilers are needed without MPI support, simply load the llvm module.

The Cray Programming Environment does not offer LLVM compiler support. Thus, cc/CC/ftn compiler wrappers using LLVM compilers currently are not available. To use Clang with MPI, one can load the mpiwrappers/cray-mpich-llvm module, which loads the following modules:

  • llvm, upstream LLVM compilers
  • cray-mpich, MPI compiler wrappers mpicc/mpicxx/mpif90. mpif90 uses gfortran because flang is not ready for production use.
  • cray-pals, MPI launchers mpiexec/aprun/mpirun

Limitation: There is no GPU-aware MPI library linking support by default. If needed, users should manually add the GTL (GPU Transport Layer) library to the application link line.

Update 04/25/2024: To access LLVM modules, module use /soft/modulefiles is required.

OpenMP offload

When targeting the OpenMP or CUDA programming models for GPUs, the cudatoolkit-standalone module should also be loaded.