Cray Compiler Overview

Software enhancements and support

This section describes software enhancements and support details for the HPE CCE 18.0.0 release.

Language technology

  • HPE Cray Fortran fully supports the Fortran 2018 standard.

  • The C and C++ compilers are based on Clang and LLVM 18.1.6.

    • C fully supports c89 with partial support for c99, c11, and c17.

    • C++ fully supports C++17 with partial support for C++20 and C++23.

  • LLVM version 18.1.6 base.

Miscellaneous features and enhancements

With the 18.0.0 release, added:

  • A new CCE compiler_interop manpage. This new manpage details information about CCE compiler interoperability. See Accessing Product Documentation for more information on accessing manpages.

  • New OpenMP 5.1 features to include:

    • interop construct and API routines.

    • compare and fail clauses for atomic construct.

    • present modifier and defaultmap(present).

    • The nowait clause for the taskwait directive.

    • default(private) and default(firstprivate) (C/C++).

    • omp_target_memcpy_async and omp_target_memcpy_rect_async.

    • nothing directive (C/C++).

  • A new -fopenmp-force-usm compiler flag (C/C++/Fortran). This flag enables OpenMP unified shared memory (USM) and treats each source file as though it contains an explicit omp requires unified_shared_memory directive.

  • For OpenACC 3.1, the implementation of OpenACC serial construct.

  • New OpenACC 2.7 features to include:

    • Snap subarray and subscript expressions for use at the end of data regions.

    • Reduction on a compute construct implies a copy clause.

  • New OpenACC 2.5 features to include:

    • Automatic allocate or deallocate for device_resident and device_create allocatables and pointers.

    • Support acc_memcpy_device routine.

    • Support num_gangs, num_workers, and vector_length on kernels directives.

    • Support async copy routines.

    • The ability to handle scoping for lexically visible data regions.

  • RHEL 8.10 x86_64 support.

  • RHEL 9.4 x86_64 support.

  • RHLEL 9.4 aarch64 support.

Also with this release, updated the OMP_PLACE CPU affinity mapping policy to allow for the use of absolute indexes instead of relative.

New Fortran-related features now allow for:

  • Control over leading zeros in output of real values: LEADING_ZERO= specifier

  • Auto-allocation of character variables in more places - statements

  • TYPEOF and CLASSOF declarations

  • More use of binary, octal, and hexadecimal (BOZ) constants

  • Partial implementation of conditional expressions and arguments

  • Enumeration type

  • SIMPLE attribute for procedures

  • OpenMP floating-point atomic optimization hints for AMD MI250X GPUs

  • Advanced AMD GPU DWARF support, including:

    • Fortran scalar variables and fixed-size arrays in offload regions

    • Fortran common blocks

RHEL gcc-toolset-13 support and integration

  • For RHEL-based systems, continue to use the gcc-toolset provided by Red Hat, updating it to gcc-toolset-13 as the baseline.

  • RHEL-based systems with shared libraries built by CCE versions prior to 17.0.0 do not need to be rebuilt.

Compatibilities, incompatibilities, and differences

  • None

Accessing product documentation

Access HPE documents and manpages for HPE CCE releases from:

  • HPE Support Center

    Access PDF versions of all CCE documents at the HPE Support Center. See Available publications for a complete list.

    To narrow search results from the HPE Support Center website, enter the publication and release number (for example, S-5212 18.0.0).

  • Release Package

    All HPE Cray Programming Environment (CPE) and HPE Cray Compiling Environment (CCE) documents are included in documentation tar files provided in the release package. See Available publications for details.

  • Manpages

    Manpages are textual help files available from the command line on HPE and HPE Cray systems. To access manpages, enter the man command followed by the name of the manpage. For more information about manpages, see the man(1) manpage by entering:

    hostname> man man

    Basic CCE man pages provided include crayftn(1), craycc(1), crayCC(1), intro_openmp(7), intro_openacc(7), and intro_MPI(3).

    The ftn(1), cc(1), and CC(1) manpages are disambiguation manpages that provide basic introductions to the compiler environment. For information specific to the CCE Fortran compiler, see the crayftn(1) manpage. For information specific to the CCE C, C++, or UPC compiler, see the clang(1) manpage.

    Alternatively, the craycc(1) and crayCC(1) manpages are aliases that redirect to the Clang C, C++, and UPC manpage.

  • Third-party documentation

    Third-party documentation is not provided by HPE.

Additional resources

Product

Documentation Source

Clang/LLVM C and C++ compiler

Documentation for the CCE C and C++ compilers is available here, in the clang(1) manpage, and can be accessed by entering the -help command line option.

GNU compilers

Documentation for the GNU C and Fortran compilers is available here

glibc

glibc documentation is available here

GLIB

GLIB documentation is available here

RPM

RPM documentation is available here

Installing CCE

CCE is distributed as a set of RPM packages. You can install the main cce-<version> package to use the CCE C, C++, and Fortran compilers. Optionally, you can install:

  • cce-<version>-gpu-amd to compile applications for AMD GPUs.

  • cce-<version>-gpu-nvidia to compile applications for NVIDIA GPUs.

  • cce-<version>-pgas-ofi to compile applications for PGAS on the OFI network target.

  • cce-<version>-doc for online documentation, including manpages.

  • cce-<version>-devel for compiler development.

For a minimal installation suitable for running applications built by CCE, install only cce-<version>-runtime. Also install any GPU and PGAS packages that the application requires.

Procedure

To install CCE RPMs, use a package manager or use the rpm command. A package manager handles RPM dependencies automatically. The rpm command does not handle RPM dependencies automatically. Zypper is the recommended package manager on SLES systems. DNF is the recommended package manager on RHEL systems. For details on configuring each package manager, refer to the package manager’s documentation.

To install a package with Zypper, run:

hostname## zypper install <package_name>

To install a package with DNF, run:

hostname## dnf install <package_name>

To install an RPM with the rpm command, run:

hostname## rpm -ivh <rpm_name>.<arch>.rpm

Setting the default CCE version

To set CCE version <version> as default:

hostname## /opt/cray/pe/admin-pe/set_default_files/set_default_cce_<version>

To use CCE:

hostname> module load PrgEnv-cray

This module defines the system paths and environment variables needed to build an application using CCE for supported systems and loads and links additional libraries as required. The exact modules loaded vary depending on the system type.

To switch to the x.y.z version of CCE:

hostname> module swap cce cce/x.y.z

Note that users at sites that opt to not enable CPE by default must source $CRAY_ENABLE_PE to enable use of the CPE module environment.

Compiling and linking code

To compile and link code, always use either the ftn, cc, or CC command. Due to the multiple compiling environments potentially available on HPE systems, the craype module provides compiler drivers that forward the ftn, cc, and CC commands to the commands required by specific compilers.