diff --git a/.github/workflows/build-test.yml b/.github/workflows/build-test.yml
index e6737f17e..e618873cd 100644
--- a/.github/workflows/build-test.yml
+++ b/.github/workflows/build-test.yml
@@ -29,127 +29,79 @@ concurrency:
 jobs:
 
   build-2604-gcc:
-    name: Build | ${{ matrix.os }} | ${{ matrix.cc }}${{ matrix.asan && ' | asan' || '' }}
+    name: Build | ubuntu-26.04 | gcc
     uses: ./.github/workflows/reusable-build.yml
     with:
       sha: ${{ github.sha }}
-      os: ${{ matrix.os }}
-      os-name: linux
-      cc: ${{ matrix.cc }}
-      dev-asan: ${{ matrix.asan }}
+      os: ubuntu-26.04
+      cc: gcc
+      dev-asan: 0
       dev-gcov: 0
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - {os: ubuntu-26.04, cc: gcc, asan: 0}
 
   build-2604-clang:
-    name: Build | ${{ matrix.os }} | ${{ matrix.cc }}${{ matrix.asan && ' | asan' || '' }}
+    name: Build | ubuntu-26.04 | clang
     uses: ./.github/workflows/reusable-build.yml
     with:
       sha: ${{ github.sha }}
-      os: ${{ matrix.os }}
-      os-name: linux
-      cc: ${{ matrix.cc }}
-      dev-asan: ${{ matrix.asan }}
+      os: ubuntu-26.04
+      cc: clang
+      dev-asan: 1
       dev-gcov: 0
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - {os: ubuntu-26.04, cc: clang, asan: 1}
 
   build-2404-gcc:
-    name: Build | ${{ matrix.os }} | ${{ matrix.cc }}${{ matrix.asan && ' | asan' || '' }}
+    name: Build | ubuntu-24.04 | gcc
     uses: ./.github/workflows/reusable-build.yml
     with:
       sha: ${{ github.sha }}
-      os: ${{ matrix.os }}
-      os-name: linux
-      cc: ${{ matrix.cc }}
-      dev-asan: ${{ matrix.asan }}
+      os: ubuntu-24.04
+      cc: gcc
+      dev-asan: 0
       dev-gcov: 0
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - {os: ubuntu-24.04, cc: gcc, asan: 0}
 
   build-2404-clang:
-    name: Build | ${{ matrix.os }} | ${{ matrix.cc }}${{ matrix.asan && ' | asan' || '' }}
+    name: Build | ubuntu-24.04 | clang
     uses: ./.github/workflows/reusable-build.yml
     with:
       sha: ${{ github.sha }}
-      os: ${{ matrix.os }}
-      os-name: linux
-      cc: ${{ matrix.cc }}
-      dev-asan: ${{ matrix.asan }}
+      os: ubuntu-24.04
+      cc: clang
+      dev-asan: 0
       dev-gcov: 0
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - {os: ubuntu-24.04, cc: clang, asan: 0}
 
   build-2204-gcc:
-    name: Build | ${{ matrix.os }} | ${{ matrix.cc }}${{ matrix.asan && ' | asan' || '' }}
+    name: Build | ubuntu-22.04 | gcc
     uses: ./.github/workflows/reusable-build.yml
     with:
       sha: ${{ github.sha }}
-      os: ${{ matrix.os }}
-      os-name: linux
-      cc: ${{ matrix.cc }}
-      dev-asan: ${{ matrix.asan }}
+      os: ubuntu-22.04
+      cc: gcc
+      dev-asan: 0
       dev-gcov: 0
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - {os: ubuntu-22.04, cc: gcc, asan: 0}
 
-  build-osx-gcc:
-    name: Build | ${{ matrix.os }} | ${{ matrix.cc }}${{ matrix.asan && ' | asan' || '' }}
+  build-macos-15-gcc:
+    name: Build | macos-15 | gcc
     uses: ./.github/workflows/reusable-build.yml
     with:
       sha: ${{ github.sha }}
-      os: ${{ matrix.os }}
-      os-name: osx
-      cc: ${{ matrix.cc }}
-      dev-asan: ${{ matrix.asan }}
+      os: macos-15
+      cc: gcc
+      dev-asan: 0
       dev-gcov: 0
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - {os: macos-15, cc: gcc, asan: 0}
 
-  build-osx-clang:
-    name: Build | ${{ matrix.os }} | ${{ matrix.cc }}${{ matrix.asan && ' | asan' || '' }}
+  build-macos-15-clang:
+    name: Build | macos-15 | clang
     uses: ./.github/workflows/reusable-build.yml
     with:
       sha: ${{ github.sha }}
-      os: ${{ matrix.os }}
-      os-name: osx
-      cc: ${{ matrix.cc }}
-      dev-asan: ${{ matrix.asan }}
+      os: macos-15
+      cc: clang
+      dev-asan: 0
       dev-gcov: 0
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - {os: macos-15, cc: clang, asan: 0}
 
   build-windows:
-    name: Build | ${{ matrix.os }} | ${{ matrix.cc }}
-    runs-on: ${{ matrix.os }}
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - {os: windows-2025-vs2026, cc: msvc}
+    name: Build | windows-2025-vs2026 | msvc
+    runs-on: windows-2025-vs2026
     env:
-      CI_OS_NAME: win
       CCACHE_COMPRESS: 1
       CCACHE_DIR: ${{ github.workspace }}/.ccache
       CCACHE_LIMIT_MULTIPLE: 0.95
@@ -177,7 +129,7 @@ jobs:
           name: verilator-win.zip
 
   test-2604-gcc:
-    name: Test | ${{ matrix.os }} | ${{ matrix.cc }} | ${{ matrix.reloc && 'reloc | ' || '' }} ${{ matrix.suite }}
+    name: Test | ${{ matrix.os }} | ${{ matrix.cc }} | ${{ matrix.suite }}
     needs: build-2604-gcc
     uses: ./.github/workflows/reusable-test.yml
     with:
@@ -201,7 +153,7 @@ jobs:
           - {os: ubuntu-26.04, cc: gcc, reloc: 0, suite: vltmt-2}
 
   test-2604-clang:
-    name: Test | ${{ matrix.os }} | ${{ matrix.cc }} | ${{ matrix.reloc && 'reloc | ' || '' }} ${{ matrix.suite }}
+    name: Test | ${{ matrix.os }} | ${{ matrix.cc }} | ${{ matrix.suite }}
     needs: build-2604-clang
     uses: ./.github/workflows/reusable-test.yml
     with:
@@ -225,7 +177,7 @@ jobs:
           - {os: ubuntu-26.04, cc: clang, reloc: 0, suite: vltmt-2}
 
   test-2404-gcc:
-    name: Test | ${{ matrix.os }} | ${{ matrix.cc }} | ${{ matrix.reloc && 'reloc | ' || '' }} ${{ matrix.suite }}
+    name: Test | ${{ matrix.os }} | ${{ matrix.cc }} | ${{ matrix.suite }}
     needs: build-2404-gcc
     uses: ./.github/workflows/reusable-test.yml
     with:
@@ -249,7 +201,7 @@ jobs:
           - {os: ubuntu-24.04, cc: gcc, reloc: 0, suite: vltmt-2}
 
   test-2404-clang:
-    name: Test | ${{ matrix.os }} | ${{ matrix.cc }} | ${{ matrix.reloc && 'reloc | ' || '' }} ${{ matrix.suite }}
+    name: Test | ${{ matrix.os }} | ${{ matrix.cc }} | ${{ matrix.suite }}
     needs: build-2404-clang
     uses: ./.github/workflows/reusable-test.yml
     with:
@@ -273,7 +225,7 @@ jobs:
           - {os: ubuntu-24.04, cc: clang, reloc: 1, suite: vltmt-2}
 
   test-2204-gcc:
-    name: Test | ${{ matrix.os }} | ${{ matrix.cc }} | ${{ matrix.reloc && 'reloc | ' || '' }} ${{ matrix.suite }}
+    name: Test | ${{ matrix.os }} | ${{ matrix.cc }} | ${{ matrix.suite }}
     needs: build-2204-gcc
     uses: ./.github/workflows/reusable-test.yml
     with:
diff --git a/.github/workflows/coverage.yml b/.github/workflows/coverage.yml
index 38d4c9a50..3b21b8f48 100644
--- a/.github/workflows/coverage.yml
+++ b/.github/workflows/coverage.yml
@@ -43,7 +43,6 @@ jobs:
       # between the root of the pull request and the target branch
       sha: ${{ github.event_name == 'pull_request' && github.event.pull_request.head.sha || github.sha }}
       os: ubuntu-24.04
-      os-name: linux
       cc: gcc
       dev-asan: 0
       dev-gcov: 1
diff --git a/.github/workflows/format.yml b/.github/workflows/format.yml
index 5a604fa73..693190453 100644
--- a/.github/workflows/format.yml
+++ b/.github/workflows/format.yml
@@ -15,18 +15,12 @@ jobs:
   format:
     runs-on: ubuntu-24.04
     name: Ubuntu 24.04 | format
-    env:
-      CI_OS_NAME: linux
-      CI_RUNS_ON: ubuntu-24.04
-      CI_COMMIT: ${{ github.sha }}
     steps:
       - name: Checkout
         uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0  # v7
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
       - name: Install packages for build
-        env:
-          CI_BUILD_STAGE_NAME: build
         run: |
           sudo apt install clang-format-18 || \
           sudo apt install clang-format-18
diff --git a/.github/workflows/reusable-build.yml b/.github/workflows/reusable-build.yml
index f19fa4ad1..a956d927e 100644
--- a/.github/workflows/reusable-build.yml
+++ b/.github/workflows/reusable-build.yml
@@ -17,9 +17,6 @@ on:
       cc: # 'clang' or 'gcc'
         required: true
         type: string
-      os-name: # 'linux' or 'osx'
-        required: true
-        type: string
       dev-asan:
         required: true
         type: number
@@ -32,12 +29,9 @@ on:
         value: ${{ jobs.build.outputs.archive }}
 
 env:
-  CI_OS_NAME: ${{ inputs.os-name }}
   CCACHE_COMPRESS: 1
   CCACHE_DIR: ${{ github.workspace }}/.ccache
   CCACHE_LIMIT_MULTIPLE: 0.95
-  INSTALL_DIR: ${{ github.workspace }}/install
-  RELOC_DIR: ${{ github.workspace }}/relloc
 
 defaults:
   run:
@@ -52,11 +46,6 @@ jobs:
     outputs:
       archive: ${{ steps.create-archive.outputs.archive }}
     env:
-      CI_BUILD_STAGE_NAME: build
-      CI_DEV_ASAN: ${{ inputs.dev-asan }}
-      CI_DEV_GCOV: ${{ inputs.dev-gcov }}
-      CI_RUNS_ON: ${{ inputs.os }}
-      CXX: ${{ inputs.cc == 'clang' && 'clang++' || 'g++' }}
       CACHE_BASE_KEY: build-${{ inputs.os }}-${{ inputs.cc }}
       CCACHE_MAXSIZE: 1000M  # Per build matrix entry (* 5 = 5000M in total)
     steps:
@@ -78,10 +67,16 @@ jobs:
             ${{ env.CACHE_KEY }}-
 
       - name: Install packages for build
-        run: ./ci/ci-install.bash
+        run: ./ci/ci-install.bash build
 
       - name: Build
-        run: ./ci/ci-script.bash
+        run: |
+          ./ci/ci-build.bash \
+            --prefix ${{ github.workspace }}/install \
+            --compiler ${{ inputs.cc }} \
+            --ccwarn \
+            ${{ inputs.dev-asan && '--asan' || '' }} \
+            ${{ inputs.dev-gcov && '--gcov' || '' }}
 
       - name: Create repository archive
         id: create-archive
diff --git a/.github/workflows/reusable-lint-py.yml b/.github/workflows/reusable-lint-py.yml
index f37027aa7..ae7ff30b6 100644
--- a/.github/workflows/reusable-lint-py.yml
+++ b/.github/workflows/reusable-lint-py.yml
@@ -8,9 +8,6 @@ on:
   workflow_call:
 
 env:
-  CI_OS_NAME: linux
-  CI_BUILD_STAGE_NAME: build
-  CI_RUNS_ON: ubuntu-22.04
   CCACHE_COMPRESS: 1
   CCACHE_DIR: ${{ github.workspace }}/.ccache
   CCACHE_LIMIT_MULTIPLE: 0.95
@@ -32,7 +29,7 @@ jobs:
           path: repo
 
       - name: Install packages for build
-        run: ./ci/ci-install.bash
+        run: ./ci/ci-install.bash build
 
       - name: Configure
         run: |
diff --git a/.github/workflows/reusable-test.yml b/.github/workflows/reusable-test.yml
index b36134108..1c393c4f0 100644
--- a/.github/workflows/reusable-test.yml
+++ b/.github/workflows/reusable-test.yml
@@ -28,12 +28,9 @@ on:
         type: number
 
 env:
-  CI_OS_NAME: linux
   CCACHE_COMPRESS: 1
   CCACHE_DIR: ${{ github.workspace }}/.ccache
   CCACHE_LIMIT_MULTIPLE: 0.95
-  INSTALL_DIR: ${{ github.workspace }}/install
-  RELOC_DIR: ${{ github.workspace }}/relloc
 
 defaults:
   run:
@@ -46,9 +43,6 @@ jobs:
     runs-on: ${{ inputs.os }}
     name: Test
     env:
-      CI_BUILD_STAGE_NAME: test
-      CI_RUNS_ON: ${{ inputs.os }}
-      CI_RELOC: ${{inputs.reloc }}
       CXX: ${{ inputs.cc == 'clang' && 'clang++' || 'g++' }}
       CACHE_BASE_KEY: test-${{ inputs.os }}-${{ inputs.cc }}-${{inputs.reloc }}-${{ inputs.suite }}
       CCACHE_MAXSIZE: 100M  # Per build per suite (* 5 * 5 = 2500M in total)
@@ -78,17 +72,17 @@ jobs:
 
       - name: Install test dependencies
         run: |
-          ./ci/ci-install.bash
+          ./ci/ci-install.bash test
           make venv
 
       - name: Test
         id: run-test
         continue-on-error: true
-        env:
-          TESTS: ${{ inputs.suite }}
         run: |
           source .venv/bin/activate
-          ./ci/ci-script.bash
+          ./ci/ci-test.bash \
+            --suite ${{ inputs.suite }} \
+            ${{ inputs.reloc && format('--reloc {0}/reloc', github.workspace) || '' }}
 
       - name: Combine code coverage data
         if: ${{ inputs.dev-gcov }}
diff --git a/ci/ci-build.bash b/ci/ci-build.bash
new file mode 100755
index 000000000..722ed6563
--- /dev/null
+++ b/ci/ci-build.bash
@@ -0,0 +1,82 @@
+#!/usr/bin/env bash
+# DESCRIPTION: Verilator: CI build job script
+#
+# SPDX-FileCopyrightText: 2026 Wilson Snyder
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+################################################################################
+# Executed in the 'build' stage.
+################################################################################
+
+# Destructive to the checkout (reconfigures and rebuilds); never run locally
+if [ "$GITHUB_ACTIONS" != "true" ]; then
+  echo "ERROR: $(basename "$0") must only be run in GitHub Actions CI" >&2
+  exit 1
+fi
+
+set -e
+set -x
+
+source "$(dirname "$0")/ci-common.bash"
+
+################################################################################
+# Parse arguments
+
+OPT_ASAN=0
+OPT_CCWARN=0
+OPT_GCOV=0
+OPT_COMPILER=
+OPT_PREFIX=
+while [ $# -gt 0 ]; do
+  case "$1" in
+    --asan) OPT_ASAN=1 ;;
+    --ccwarn) OPT_CCWARN=1 ;;
+    --compiler)
+      [ $# -ge 2 ] || fatal "--compiler requires an argument"
+      OPT_COMPILER="$2"
+      shift
+      ;;
+    --gcov) OPT_GCOV=1 ;;
+    --prefix)
+      [ $# -ge 2 ] || fatal "--prefix requires an argument"
+      OPT_PREFIX="$2"
+      shift
+      ;;
+    *) fatal "Unknown option: '$1'" ;;
+  esac
+  shift
+done
+
+[ -n "$OPT_COMPILER" ] || fatal "--compiler is required"
+[ -n "$OPT_PREFIX" ] || fatal "--prefix is required"
+
+# Map the compiler name to the executable name configure CXX expects
+case "$OPT_COMPILER" in
+  clang) CXX=clang++ ;;
+  gcc) CXX=g++ ;;
+  *) fatal "Unknown compiler: '$OPT_COMPILER'" ;;
+esac
+
+################################################################################
+# Configure
+
+CONFIGURE_ARGS="--prefix=$OPT_PREFIX --enable-longtests"
+if [ "$OPT_CCWARN" = 1 ]; then
+  CONFIGURE_ARGS="$CONFIGURE_ARGS --enable-ccwarn"
+fi
+if [ "$OPT_ASAN" = 1 ]; then
+  CONFIGURE_ARGS="$CONFIGURE_ARGS --enable-dev-asan"
+  CXX="$CXX -DVL_LEAK_CHECKS"
+fi
+if [ "$OPT_GCOV" = 1 ]; then
+  CONFIGURE_ARGS="$CONFIGURE_ARGS --enable-dev-gcov"
+fi
+autoconf
+./configure $CONFIGURE_ARGS CXX="$CXX"
+
+################################################################################
+# Build
+
+ccache -z
+"$MAKE" -j "$NPROC" -k
+ccache -svv
diff --git a/ci/ci-common.bash b/ci/ci-common.bash
new file mode 100644
index 000000000..ef2fe23c8
--- /dev/null
+++ b/ci/ci-common.bash
@@ -0,0 +1,37 @@
+# DESCRIPTION: Verilator: CI common definitions, sourced by the stage scripts
+#
+# SPDX-FileCopyrightText: 2026 Wilson Snyder
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+################################################################################
+# Common definitions sourced by the CI stage scripts; not executed directly.
+################################################################################
+
+fatal() {
+  echo "ERROR: $(basename "$0"): $1" >&2; exit 1;
+}
+
+case "$(uname -s)" in
+  Linux)
+    HOST_OS=linux
+    MAKE=make
+    NPROC=$(nproc)
+    # Distro id/version; subshell keeps os-release out of our namespace
+    if [ -r /etc/os-release ]; then
+      DISTRO_ID=$(. /etc/os-release; echo "$ID")
+      DISTRO_VERSION=$(. /etc/os-release; echo "$VERSION_ID")
+    fi
+    ;;
+  Darwin)
+    HOST_OS=macOS
+    MAKE=make
+    NPROC=$(sysctl -n hw.logicalcpu)
+    # Disable ccache, doesn't always work in GitHub Actions
+    export OBJCACHE=
+    ;;
+  *)
+    fatal "Unknown host OS: '$(uname -s)'"
+    ;;
+esac
+
+export MAKE
diff --git a/ci/ci-install.bash b/ci/ci-install.bash
index b3ae2e06d..db71c8159 100755
--- a/ci/ci-install.bash
+++ b/ci/ci-install.bash
@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 # DESCRIPTION: Verilator: CI dependency install script
 #
-# SPDX-FileCopyrightText: 2020 Geza Lore
+# SPDX-FileCopyrightText: 2026 Wilson Snyder
 # SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
 
 ################################################################################
@@ -10,30 +10,33 @@
 # required by the particular build stage.
 ################################################################################
 
+# Installs system packages with sudo; never run locally
+if [ "$GITHUB_ACTIONS" != "true" ]; then
+  echo "ERROR: $(basename "$0") must only be run in GitHub Actions CI" >&2
+  exit 1
+fi
+
 set -e
 set -x
 
 cd $(dirname "$0")/..
 
+source "$(dirname "$0")/ci-common.bash"
+
+################################################################################
+# Parse arguments
+
+# Which stage to install dependencies for: 'build' or 'test'
+STAGE="$1"
+
+################################################################################
+# Install dependencies
+
 # Avoid occasional cpan failures "Issued certificate has expired."
 export PERL_LWP_SSL_VERIFY_HOSTNAME=0
 echo "check_certificate = off" >> ~/.wgetrc
 
-fatal() {
-  echo "ERROR: $(basename "$0"): $1" >&2; exit 1;
-}
-
-if [ "$CI_OS_NAME" = "linux" ]; then
-  MAKE=make
-elif [ "$CI_OS_NAME" = "osx" ]; then
-  MAKE=make
-elif [ "$CI_OS_NAME" = "freebsd" ]; then
-  MAKE=gmake
-else
-  fatal "Unknown CI_OS_NAME: '$CI_OS_NAME'"
-fi
-
-if [ "$CI_OS_NAME" = "linux" ]; then
+if [ "$HOST_OS" = "linux" ]; then
   # Avoid slow "processing triggers for man db"
   echo "path-exclude /usr/share/doc/*"  | sudo tee -a /etc/dpkg/dpkg.cfg.d/01_nodoc
   echo "path-exclude /usr/share/man/*"  | sudo tee -a /etc/dpkg/dpkg.cfg.d/01_nodoc
@@ -44,100 +47,100 @@ install-wavediff() {
   source ci/docker/buildenv/wavetools.conf
   local _base_url="https://github.com/hudson-trading/wavetools/releases/download/${WAVETOOLS_VERSION}"
   local _platform
-  if [ "$CI_OS_NAME" = "linux" ]; then
+  if [ "$HOST_OS" = "linux" ]; then
     _platform="linux-x86_64"
-  elif [ "$CI_OS_NAME" = "osx" ]; then
+  elif [ "$HOST_OS" = "macOS" ]; then
     _platform="macos-arm64"
-  elif [ "$CI_OS_NAME" = "windows" ]; then
-    _platform="windows-x86_64"
   else
-    echo "WARNING: No wavetools binary available for CI_OS_NAME=$CI_OS_NAME, skipping"
+    echo "WARNING: No wavetools binary available for HOST_OS=$HOST_OS, skipping"
     return 0
   fi
   local _tmpdir
   _tmpdir=$(mktemp -d)
   local _archive="wavetools-${WAVETOOLS_VERSION}-${_platform}"
-  if [ "$CI_OS_NAME" = "windows" ]; then
-    wget -q -O "${_tmpdir}/${_archive}.zip" "${_base_url}/${_archive}.zip"
-    unzip -o "${_tmpdir}/${_archive}.zip" -d "${_tmpdir}"
-  else
-    wget -q -O "${_tmpdir}/${_archive}.tar.gz" "${_base_url}/${_archive}.tar.gz"
-    tar -xzf "${_tmpdir}/${_archive}.tar.gz" -C "${_tmpdir}"
-  fi
+  wget -q -O "${_tmpdir}/${_archive}.tar.gz" "${_base_url}/${_archive}.tar.gz"
+  tar -xzf "${_tmpdir}/${_archive}.tar.gz" -C "${_tmpdir}"
   sudo cp "${_tmpdir}/${_archive}/wavediff" /usr/local/bin/wavediff
   rm -rf "${_tmpdir}"
 }
 
-if [ "$CI_BUILD_STAGE_NAME" = "build" ]; then
+if [ "$STAGE" = "build" ]; then
   ##############################################################################
   # Dependencies of jobs in the 'build' stage, i.e.: packages required to
   # build Verilator
 
-  if [ "$CI_OS_NAME" = "linux" ]; then
-    sudo apt-get update ||
-    sudo apt-get update
-    sudo apt-get install --yes ccache help2man libfl-dev ||
-    sudo apt-get install --yes ccache help2man libfl-dev
-    if [[ ! "$CI_RUNS_ON" =~ "ubuntu-22.04" ]]; then
-      # Some conflict of libunwind verison on 22.04, can live without it for now
-      sudo apt-get install --yes libjemalloc-dev ||
-      sudo apt-get install --yes libjemalloc-dev
-    fi
-    if [[ "$CI_RUNS_ON" =~ "ubuntu-22.04" ]] || [[ "$CI_RUNS_ON" =~ "ubuntu-24.04" ]] || [[ "$CI_RUNS_ON" =~ "ubuntu-26.04" ]]; then
-      if [[ ! "$CI_RUNS_ON" =~ "-riscv" ]]; then
-        sudo apt-get install --yes libsystemc libsystemc-dev ||
-        sudo apt-get install --yes libsystemc libsystemc-dev
+  if [ "$HOST_OS" = "linux" ]; then
+    if [ "$DISTRO_ID" = "ubuntu" ]; then
+      PACKAGES=(
+        bear
+        ccache
+        help2man
+        libfl-dev
+        libsystemc-dev
+        mold
+      )
+      # libunwind conflict on 22.04, can live without libjemalloc there
+      if [ "$DISTRO_VERSION" != "22.04" ]; then
+        PACKAGES+=(libjemalloc-dev)
       fi
+      sudo apt-get update ||
+      sudo apt-get update
+      sudo apt-get install --yes "${PACKAGES[@]}" ||
+      sudo apt-get install --yes "${PACKAGES[@]}"
     fi
-    if [[ "$CI_RUNS_ON" =~ "ubuntu-22.04" ]] || [[ "$CI_RUNS_ON" =~ "ubuntu-24.04" ]] || [[ "$CI_RUNS_ON" =~ "ubuntu-26.04" ]]; then
-      sudo apt-get install --yes bear mold ||
-      sudo apt-get install --yes bear mold
-    fi
-  elif [ "$CI_OS_NAME" = "osx" ]; then
+  elif [ "$HOST_OS" = "macOS" ]; then
+    PACKAGES=(
+      autoconf
+      bison
+      ccache
+      flex
+      gperftools
+      help2man
+      perl
+    )
     brew update ||
     brew update
-    brew install ccache perl gperftools autoconf bison flex help2man ||
-    brew install ccache perl gperftools autoconf bison flex help2man
-  elif [ "$CI_OS_NAME" = "freebsd" ]; then
-    sudo pkg install -y autoconf bison ccache gmake perl5
+    brew install "${PACKAGES[@]}" ||
+    brew install "${PACKAGES[@]}"
   else
-    fatal "Unknown CI_OS_NAME: '$CI_OS_NAME'"
+    fatal "Unknown HOST_OS: '$HOST_OS'"
   fi
-
-  if [ -n "$CCACHE_DIR" ]; then
-    mkdir -p "$CCACHE_DIR"
-  fi
-elif [ "$CI_BUILD_STAGE_NAME" = "test" ]; then
+elif [ "$STAGE" = "test" ]; then
   ##############################################################################
   # Dependencies of jobs in the 'test' stage, i.e.: packages required to
   # run the tests
 
-  if [ "$CI_OS_NAME" = "linux" ]; then
-    sudo apt-get update ||
-    sudo apt-get update
-    # libfl-dev needed for internal coverage's test runs
-    sudo apt-get install --yes gdb gtkwave lcov libfl-dev ccache jq z3 ||
-    sudo apt-get install --yes gdb gtkwave lcov libfl-dev ccache jq z3
-    # Required for test_regress/t/t_dist_attributes.py
-    if [[ "$CI_RUNS_ON" =~ "ubuntu-22.04" ]] || [[ "$CI_RUNS_ON" =~ "ubuntu-24.04" ]] || [[ "$CI_RUNS_ON" =~ "ubuntu-26.04" ]]; then
-      sudo apt-get install --yes python3-clang mold ||
-      sudo apt-get install --yes python3-clang mold
+  if [ "$HOST_OS" = "linux" ]; then
+    if [ "$DISTRO_ID" = "ubuntu" ]; then
+      PACKAGES=(
+        ccache
+        gdb
+        jq
+        lcov
+        libfl-dev
+        libsystemc-dev
+        mold
+        python3-clang
+        z3
+      )
+      sudo apt-get update ||
+      sudo apt-get update
+      sudo apt-get install --yes "${PACKAGES[@]}" ||
+      sudo apt-get install --yes "${PACKAGES[@]}"
     fi
-    if [[ "$CI_RUNS_ON" =~ "ubuntu-22.04" ]] || [[ "$CI_RUNS_ON" =~ "ubuntu-24.04" ]] || [[ "$CI_RUNS_ON" =~ "ubuntu-26.04" ]]; then
-      if [[ ! "$CI_RUNS_ON" =~ "-riscv" ]]; then
-        sudo apt-get install --yes libsystemc libsystemc-dev ||
-        sudo apt-get install --yes libsystemc libsystemc-dev
-      fi
-    fi
-  elif [ "$CI_OS_NAME" = "osx" ]; then
+  elif [ "$HOST_OS" = "macOS" ]; then
+    PACKAGES=(
+      ccache
+      jq
+      perl
+      z3
+    )
+    brew update ||
     brew update
-    # brew cask install gtkwave # fst2vcd hangs at launch, so don't bother
-    brew install ccache perl jq z3
-  elif [ "$CI_OS_NAME" = "freebsd" ]; then
-    # fst2vcd fails with "Could not open '<input file>', exiting."
-    sudo pkg install -y ccache gmake perl5 python3 jq z3
+    brew install "${PACKAGES[@]}" ||
+    brew install "${PACKAGES[@]}"
   else
-    fatal "Unknown CI_OS_NAME: '$CI_OS_NAME'"
+    fatal "Unknown HOST_OS: '$HOST_OS'"
   fi
   # Common installs
   install-wavediff
@@ -146,5 +149,11 @@ elif [ "$CI_BUILD_STAGE_NAME" = "test" ]; then
 else
   ##############################################################################
   # Unknown build stage
-  fatal "Unknown CI_BUILD_STAGE_NAME: '$CI_BUILD_STAGE_NAME'"
+  fatal "Unknown stage '$STAGE' (expected 'build' or 'test')"
 fi
+
+# Report where the tools we may have installed live (ok if some are missing)
+for bin in autoconf bear bison ccache flex gdb help2man jq lcov mold perl wavediff z3; do
+  echo -n "$bin "
+  which "$bin" || true
+done
diff --git a/ci/ci-script.bash b/ci/ci-script.bash
deleted file mode 100755
index aa7a5987a..000000000
--- a/ci/ci-script.bash
+++ /dev/null
@@ -1,208 +0,0 @@
-#!/usr/bin/env bash
-# DESCRIPTION: Verilator: CI main job script
-#
-# SPDX-FileCopyrightText: 2020 Geza Lore
-# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
-
-################################################################################
-# This is the main script executed in the 'script' phase by all jobs. We use a
-# single script to keep the CI setting simple. We pass job parameters via
-# environment variables using 'env' keys.
-################################################################################
-
-set -e
-set -x
-
-fatal() {
-  echo "ERROR: $(basename "$0"): $1" >&2; exit 1;
-}
-
-if [ "$CI_OS_NAME" = "linux" ]; then
-  export MAKE=make
-  NPROC=$(nproc)
-elif [ "$CI_OS_NAME" = "osx" ]; then
-  export MAKE=make
-  NPROC=$(sysctl -n hw.logicalcpu)
-  # Disable ccache, doesn't always work in GitHub Actions
-  export OBJCACHE=
-elif [ "$CI_OS_NAME" = "freebsd" ]; then
-  export MAKE=gmake
-  NPROC=$(sysctl -n hw.ncpu)
-else
-  fatal "Unknown CI_OS_NAME: '$CI_OS_NAME'"
-fi
-NPROC=$(expr $NPROC '+' 1)
-
-if [ "$CI_BUILD_STAGE_NAME" = "build" ]; then
-  ##############################################################################
-  # Build verilator
-
-  autoconf
-  CONFIGURE_ARGS="--enable-longtests --enable-ccwarn"
-  if [ "$CI_DEV_ASAN" = 1 ]; then
-    CONFIGURE_ARGS="$CONFIGURE_ARGS --enable-dev-asan"
-    CXX="$CXX -DVL_LEAK_CHECKS"
-  fi
-  if [ "$CI_DEV_GCOV" = 1 ]; then
-    CONFIGURE_ARGS="$CONFIGURE_ARGS --enable-dev-gcov"
-  fi
-  ./configure $CONFIGURE_ARGS --prefix="$INSTALL_DIR"
-  ccache -z
-  "$MAKE" -j "$NPROC" -k
-  # 22.04: ccache -s -v
-  ccache -s
-  if [ "$CI_OS_NAME" = "osx" ]; then
-    file bin/verilator_bin
-    file bin/verilator_bin_dbg
-    md5 bin/verilator_bin
-    md5 bin/verilator_bin_dbg
-    stat bin/verilator_bin
-    stat bin/verilator_bin_dbg
-  fi
-elif [ "$CI_BUILD_STAGE_NAME" = "test" ]; then
-  ##############################################################################
-  # Run tests
-
-  export VERILATOR_TEST_NO_CONTRIBUTORS=1  # Separate workflow check
-  export VERILATOR_TEST_NO_LINT_PY=1  # Separate workflow check
-
-  if [ "$CI_OS_NAME" = "osx" ]; then
-    export VERILATOR_TEST_NO_GDB=1  # Pain to get GDB to work on OS X
-    # TODO below may no longer be required as configure checks for -pg
-    export VERILATOR_TEST_NO_GPROF=1  # Apple Clang has no -pg
-    # export PATH="/Applications/gtkwave.app/Contents/Resources/bin:$PATH" # fst2vcd
-    file bin/verilator_bin
-    file bin/verilator_bin_dbg
-    md5 bin/verilator_bin
-    md5 bin/verilator_bin_dbg
-    stat bin/verilator_bin
-    stat bin/verilator_bin_dbg
-    # For some reason, the dbg exe is corrupted by this point ('file' reports
-    # it as data rather than a Mach-O). Unclear if this is an OS X issue or
-    # CI's. Remove the file and re-link...
-    rm bin/verilator_bin_dbg
-    "$MAKE" -j "$NPROC" -k
-  elif [ "$CI_OS_NAME" = "freebsd" ]; then
-    export VERILATOR_TEST_NO_GDB=1 # Disable for now, ideally should run
-    # TODO below may no longer be required as configure checks for -pg
-    export VERILATOR_TEST_NO_GPROF=1 # gprof is a bit different on FreeBSD, disable
-  fi
-
-  TEST_REGRESS=test_regress
-  if [ "$CI_RELOC" == 1 ]; then
-    # Testing that the installation is relocatable.
-    "$MAKE" install
-    mkdir -p "$RELOC_DIR"
-    mv "$INSTALL_DIR" "$RELOC_DIR/relocated-install"
-    export VERILATOR_ROOT="$RELOC_DIR/relocated-install/share/verilator"
-    TEST_REGRESS="$RELOC_DIR/test_regress"
-    mv test_regress "$TEST_REGRESS"
-    NODIST="$RELOC_DIR/nodist"
-    mv nodist "$NODIST"
-    # Feeling brave?
-    find . -delete
-    ls -la .
-  fi
-
-  # Run the specified test
-  ccache -z
-  case $TESTS in
-    dist-vlt-0)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--dist --vlt --driver-clean" DRIVER_HASHSET=--hashset=0/4
-      ;;
-    dist-vlt-1)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--dist --vlt --driver-clean" DRIVER_HASHSET=--hashset=1/4
-      ;;
-    dist-vlt-2)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--dist --vlt --driver-clean" DRIVER_HASHSET=--hashset=2/4
-      ;;
-    dist-vlt-3)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--dist --vlt --driver-clean" DRIVER_HASHSET=--hashset=3/4
-      ;;
-    vltmt-0)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt --driver-clean" DRIVER_HASHSET=--hashset=0/3
-      ;;
-    vltmt-1)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt --driver-clean" DRIVER_HASHSET=--hashset=1/3
-      ;;
-    vltmt-2)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt --driver-clean" DRIVER_HASHSET=--hashset=2/3
-      ;;
-    coverage-dist)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--dist"
-      ;;
-    coverage-vlt-0)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=0/10
-      ;;
-    coverage-vlt-1)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=1/10
-      ;;
-    coverage-vlt-2)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=2/10
-      ;;
-    coverage-vlt-3)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=3/10
-      ;;
-    coverage-vlt-4)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=4/10
-      ;;
-    coverage-vlt-5)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=5/10
-      ;;
-    coverage-vlt-6)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=6/10
-      ;;
-    coverage-vlt-7)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=7/10
-      ;;
-    coverage-vlt-8)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=8/10
-      ;;
-    coverage-vlt-9)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=9/10
-      ;;
-    coverage-vltmt-0)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=0/10
-      ;;
-    coverage-vltmt-1)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=1/10
-      ;;
-    coverage-vltmt-2)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=2/10
-      ;;
-    coverage-vltmt-3)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=3/10
-      ;;
-    coverage-vltmt-4)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=4/10
-      ;;
-    coverage-vltmt-5)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=5/10
-      ;;
-    coverage-vltmt-6)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=6/10
-      ;;
-    coverage-vltmt-7)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=7/10
-      ;;
-    coverage-vltmt-8)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=8/10
-      ;;
-    coverage-vltmt-9)
-      "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=9/10
-      ;;
-    *)
-      fatal "Unknown TESTS: $TESTS"
-      ;;
-  esac
-
-  # To see load average (1 minute, 5 minute, 15 minute)
-  uptime
-  # 22.04: ccache -s -v
-  ccache -s
-
-else
-  ##############################################################################
-  # Unknown build stage
-  fatal "Unknown CI_BUILD_STAGE_NAME: '$CI_BUILD_STAGE_NAME'"
-fi
diff --git a/ci/ci-test.bash b/ci/ci-test.bash
new file mode 100755
index 000000000..f35257b94
--- /dev/null
+++ b/ci/ci-test.bash
@@ -0,0 +1,166 @@
+#!/usr/bin/env bash
+# DESCRIPTION: Verilator: CI test job script
+#
+# SPDX-FileCopyrightText: 2026 Wilson Snyder
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+################################################################################
+# Executed in the 'test' stage.
+################################################################################
+
+# Destructive to the checkout (runs 'find . -delete'); never run locally
+if [ "$GITHUB_ACTIONS" != "true" ]; then
+  echo "ERROR: $(basename "$0") must only be run in GitHub Actions CI" >&2
+  exit 1
+fi
+
+set -e
+set -x
+
+source "$(dirname "$0")/ci-common.bash"
+
+################################################################################
+# Parse arguments
+
+OPT_RELOC=
+OPT_SUITE=
+while [ $# -gt 0 ]; do
+  case "$1" in
+    --reloc)
+      [ $# -ge 2 ] || fatal "--reloc requires an argument"
+      OPT_RELOC="$2"
+      shift
+      ;;
+    --suite)
+      [ $# -ge 2 ] || fatal "--suite requires an argument"
+      OPT_SUITE="$2"
+      shift
+      ;;
+    *) fatal "Unknown option: '$1'" ;;
+  esac
+  shift
+done
+
+[ -n "$OPT_SUITE" ] || fatal "--suite is required"
+
+################################################################################
+# Run tests
+
+export VERILATOR_TEST_NO_CONTRIBUTORS=1  # Separate workflow check
+export VERILATOR_TEST_NO_LINT_PY=1  # Separate workflow check
+
+if [ "$HOST_OS" = "macOS" ]; then
+  export VERILATOR_TEST_NO_GDB=1  # No working GDB on macOS
+fi
+
+TEST_REGRESS=test_regress
+if [ -n "$OPT_RELOC" ]; then
+  # Testing that the installation is relocatable.
+  "$MAKE" install
+  # Install prefix, as configured into the Makefile at build time
+  INSTALL_DIR=$(sed -n 's/^prefix = //p' Makefile)
+  mkdir -p "$OPT_RELOC"
+  mv "$INSTALL_DIR" "$OPT_RELOC/relocated-install"
+  export VERILATOR_ROOT="$OPT_RELOC/relocated-install/share/verilator"
+  TEST_REGRESS="$OPT_RELOC/test_regress"
+  mv test_regress "$TEST_REGRESS"
+  NODIST="$OPT_RELOC/nodist"
+  mv nodist "$NODIST"
+  # Delete everything else
+  find . -delete
+  ls -la .
+fi
+
+# Run the specified suite
+ccache -z
+case $OPT_SUITE in
+  dist-vlt-0)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--dist --vlt --driver-clean" DRIVER_HASHSET=--hashset=0/4
+    ;;
+  dist-vlt-1)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--dist --vlt --driver-clean" DRIVER_HASHSET=--hashset=1/4
+    ;;
+  dist-vlt-2)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--dist --vlt --driver-clean" DRIVER_HASHSET=--hashset=2/4
+    ;;
+  dist-vlt-3)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--dist --vlt --driver-clean" DRIVER_HASHSET=--hashset=3/4
+    ;;
+  vltmt-0)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt --driver-clean" DRIVER_HASHSET=--hashset=0/3
+    ;;
+  vltmt-1)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt --driver-clean" DRIVER_HASHSET=--hashset=1/3
+    ;;
+  vltmt-2)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt --driver-clean" DRIVER_HASHSET=--hashset=2/3
+    ;;
+  coverage-dist)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--dist"
+    ;;
+  coverage-vlt-0)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=0/10
+    ;;
+  coverage-vlt-1)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=1/10
+    ;;
+  coverage-vlt-2)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=2/10
+    ;;
+  coverage-vlt-3)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=3/10
+    ;;
+  coverage-vlt-4)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=4/10
+    ;;
+  coverage-vlt-5)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=5/10
+    ;;
+  coverage-vlt-6)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=6/10
+    ;;
+  coverage-vlt-7)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=7/10
+    ;;
+  coverage-vlt-8)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=8/10
+    ;;
+  coverage-vlt-9)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vlt" DRIVER_HASHSET=--hashset=9/10
+    ;;
+  coverage-vltmt-0)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=0/10
+    ;;
+  coverage-vltmt-1)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=1/10
+    ;;
+  coverage-vltmt-2)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=2/10
+    ;;
+  coverage-vltmt-3)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=3/10
+    ;;
+  coverage-vltmt-4)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=4/10
+    ;;
+  coverage-vltmt-5)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=5/10
+    ;;
+  coverage-vltmt-6)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=6/10
+    ;;
+  coverage-vltmt-7)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=7/10
+    ;;
+  coverage-vltmt-8)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=8/10
+    ;;
+  coverage-vltmt-9)
+    "$MAKE" -C "$TEST_REGRESS" SCENARIOS="--vltmt" DRIVER_HASHSET=--hashset=9/10
+    ;;
+  *)
+    fatal "Unknown suite: $OPT_SUITE"
+    ;;
+esac
+ccache -svv
+uptime # To see load average