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Pull Request Overview
This PR introduces a new ci_clang container environment to test compilation with the Clang compiler, which has shown performance benefits in GitHub workflow testing. The changes configure Spack to build a comprehensive stack using Clang instead of GCC.
Key Changes:
- Added new
ci_clangspack environment configured to build with Clang compiler and enable inter-procedural optimization (IPO) - Configured MPI to use mpich without Fortran support to better accommodate Clang compilation
- Enabled mixed-toolchain compiler discovery in Docker builds to support both Clang and GCC compilers
Reviewed Changes
Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.
| File | Description |
|---|---|
| spack-environment/packages.yaml | Adds MPI configuration requiring mpich 4.2.1 without Fortran support to accommodate Clang builds |
| spack-environment/ci_clang/spack.yaml | New spack environment configuration that requires Clang compiler, enables IPO where available, and includes comprehensive package list for CI testing |
| containers/debian/Dockerfile | Adds --mixed-toolchain flag to compiler discovery to support mixed Clang/GCC toolchain usage |
| .gitlab-ci.yml | Adds ci_clang to the nightly build matrix for the eic environment |
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wdconinc
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Jul 3, 2026
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| ENV: | ||
| - ci | ||
| - ci_clang | ||
| - ci_without_acts | ||
| - cvmfs |
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| - BUILD_IMAGE: eic_ | ||
| ENV: | ||
| - ci | ||
| - ci_clang | ||
| - ci_without_acts | ||
| - cvmfs | ||
| - xl |
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| spack: | ||
| include: | ||
| - ../concretizer.yaml | ||
| - ../config.yaml | ||
| - ../packages.yaml | ||
| - ../packages_root_without_opengl.yaml | ||
| - ../view.yaml | ||
| packages: | ||
| all: | ||
| require: | ||
| - '%clang' | ||
| - any_of: [build_system=cmake, '@:'] | ||
| - any_of: [build_type=Release, '@:'] | ||
| specs: |
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| packages: | ||
| geant4: | ||
| require: | ||
| - ~opengl |
| mpich: | ||
| require: | ||
| - '@4.2.1:' | ||
| - -fortran |
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| - BUILD_IMAGE: eic_ | ||
| ENV: | ||
| - ci | ||
| - ci_clang | ||
| - ci_without_acts | ||
| - cvmfs | ||
| - xl |
Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
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Briefly, what does this PR introduce?
Needs:
Tests in GitHub workflows of epic and EICrecon indicate faster and smaller code when compiled with clang instead of gcc. This PR prepares a stack to run some tests with.
What kind of change does this PR introduce?