diff --git a/easybuild/easyconfigs/l/LLVM/LLVM-21.1.8-GCCcore-15.2.0.eb b/easybuild/easyconfigs/l/LLVM/LLVM-21.1.8-GCCcore-15.2.0.eb
new file mode 100644
index 000000000000..0561de16e711
--- /dev/null
+++ b/easybuild/easyconfigs/l/LLVM/LLVM-21.1.8-GCCcore-15.2.0.eb
@@ -0,0 +1,94 @@
+name = 'LLVM'
+version = '21.1.8'
+
+
+homepage = "https://llvm.org/"
+description = """
+The LLVM Core libraries provide a modern source- and target-independent
+optimizer, along with code generation support for many popular CPUs
+(as well as some less common ones!) These libraries are built around a well
+specified code representation known as the LLVM intermediate representation
+("LLVM IR"). The LLVM Core libraries are well documented, and it is
+particularly easy to invent your own language (or port an existing compiler)
+to use LLVM as an optimizer and code generator.
+"""
+
+toolchain = {'name': 'GCCcore', 'version': '15.2.0'}
+toolchainopts = {
+    'pic': True
+}
+
+source_urls = ['https://github.com/llvm/llvm-project/releases/download/llvmorg-%(version)s/']
+sources = [
+    'llvm-project-%(version)s.src.tar.xz',
+]
+patches = [
+    'LLVM-18.1.8_envintest.patch',
+    'LLVM-19.1.7_libomptarget_tests.patch',
+    'LLVM-19.1.7_clang_rpathwrap_test.patch',
+    'LLVM-21.1.x_fix-ompt-end-critical-race.patch',
+]
+checksums = [
+    {'llvm-project-21.1.8.src.tar.xz': '4633a23617fa31a3ea51242586ea7fb1da7140e426bd62fc164261fe036aa142'},
+    {'LLVM-18.1.8_envintest.patch': '8e25dfab8a29a860717b4bd2d8cdd0e795433766d7fffbda32d06a2bde47058d'},
+    {'LLVM-19.1.7_libomptarget_tests.patch': '79a67c118d034cfb74e255696369150c73432d2b422f4834efacb26f7904edbf'},
+    {'LLVM-19.1.7_clang_rpathwrap_test.patch': '5ee6a87ec8ff1c8b736ffe0513aa2098bd2b83a1ffc647a1ad2cf966f567e8a1'},
+    {'LLVM-21.1.x_fix-ompt-end-critical-race.patch':
+     '9dc675f0a53a2308a22c36892eddeeab9c3c736219c04192fc5bb1348f110838'},
+]
+
+builddependencies = [
+    ('binutils', '2.45'),
+    ('Python', '3.14.2'),
+    ('CMake', '4.2.1'),
+    ('psutil', '7.2.1'),  # Needed to enable test timeout in lit
+    ('lit', '18.1.8'),
+    ('git', '2.52.0'),
+]
+
+dependencies = [
+    ('libffi', '3.5.2'),
+    ('libxml2', '2.15.1'),
+    ('ncurses', '6.6'),
+    ('zlib', '2.3.2'),
+    ('Z3', '4.15.4'),
+    ('zstd', '1.5.7'),
+]
+
+
+build_shared_libs = True
+
+bootstrap = True
+full_llvm = False
+build_clang_extras = True
+build_runtimes = True
+build_lld = True
+build_lldb = True
+build_bolt = True
+build_openmp = True
+build_openmp_tools = True
+build_openmp_offload = True
+use_polly = True
+
+python_bindings = True
+
+build_targets = ['all']
+# disable_werror = True
+
+skip_all_tests = False
+skip_sanitizer_tests = True
+test_suite_max_failed = 10
+test_suite_timeout_single = 5 * 60
+test_suite_ignore_patterns = [
+    "X86/register-fragments-bolt-symbols.s",
+    "modularize/ProblemsCoverage.modularize",
+    "Driver/atomic.f90",
+    "Driver/gcc-toolchain-install-dir.f90",
+    "api_tests/test_ompd_get_icv_from_scope.c",
+    "std/time/time.syn/formatter",
+    # Those 2 might fail with "tzdb: the path '/etc/localtime' is not a symlink"
+    "std/time/time.zone/time.zone.db/time.zone.db.tzdb",
+    "std/time/time.zone/time.zone.db/time.zone.db.access",
+]
+
+moduleclass = 'compiler'
diff --git a/easybuild/easyconfigs/l/LLVM/LLVM-21.1.x_fix-ompt-end-critical-race.patch b/easybuild/easyconfigs/l/LLVM/LLVM-21.1.x_fix-ompt-end-critical-race.patch
new file mode 100644
index 000000000000..4e2fe2b23d03
--- /dev/null
+++ b/easybuild/easyconfigs/l/LLVM/LLVM-21.1.x_fix-ompt-end-critical-race.patch
@@ -0,0 +1,49 @@
+From 4693659e3a911360b3798a9bc50e94dad8fe7f71 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Jan=20Andr=C3=A9=20Reuter?= <j.reuter@fz-juelich.de>
+Date: Thu, 27 Nov 2025 16:42:05 +0100
+Subject: [PATCH] [OMPT] Use global thread id for `codeptr_ra` in
+ `end_critical`
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+When a critical construct has finished, it will trigger a critical-released
+event. If a tool is attached, and the `mutex_released` callback was
+registered, the tool with receive an event containing the `codeptr_ra`, the
+return address of the callback invocation.
+
+All the way back in 82e94a593433f36734e2d34898d353a2ecb65b8b, this
+`codeptr_ra` was implemented by calling `__ompt_load_return_address`
+with a fixed global thread id of `0`. However, this approach results in a
+race-condition, and can yield incorrect results to the tool.
+
+`__ompt_load_return_address(0)` points to the current return address of
+the thread 0 in `__kmp_threads`. This thread may already execute some
+other construct. A tool might therefore receive the return address of
+e.g. some `libomp` internals, or other parts of the user code.
+Additionally, a call to `__ompt_load_return_address` resets the
+`th.ompt_thread_info.return_address` to `NULL`, therefore also affecting
+the return address of thread 0. Another dispatched event, e.g.
+parallel-begin might therefore not transfer any `codeptr_ra`.
+
+To fix this, replace the fixed thread id by the `global_tid`, which is
+stored just before dispatching the `mutex_released` callback.
+
+Signed-off-by: Jan André Reuter <j.reuter@fz-juelich.de>
+---
+ openmp/runtime/src/kmp_csupport.cpp | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/openmp/runtime/src/kmp_csupport.cpp b/openmp/runtime/src/kmp_csupport.cpp
+index 3ca32ba583fe2..a92fc46374c27 100644
+--- a/openmp/runtime/src/kmp_csupport.cpp
++++ b/openmp/runtime/src/kmp_csupport.cpp
+@@ -1780,7 +1780,7 @@ void __kmpc_end_critical(ident_t *loc, kmp_int32 global_tid,
+   if (ompt_enabled.ompt_callback_mutex_released) {
+     ompt_callbacks.ompt_callback(ompt_callback_mutex_released)(
+         ompt_mutex_critical, (ompt_wait_id_t)(uintptr_t)lck,
+-        OMPT_LOAD_RETURN_ADDRESS(0));
++        OMPT_LOAD_RETURN_ADDRESS(global_tid));
+   }
+ #endif
+ 
diff --git a/easybuild/easyconfigs/l/lit/lit-18.1.8-GCCcore-15.2.0.eb b/easybuild/easyconfigs/l/lit/lit-18.1.8-GCCcore-15.2.0.eb
new file mode 100644
index 000000000000..37c0eac10ba5
--- /dev/null
+++ b/easybuild/easyconfigs/l/lit/lit-18.1.8-GCCcore-15.2.0.eb
@@ -0,0 +1,35 @@
+easyblock = 'PythonBundle'
+
+name = 'lit'
+version = '18.1.8'
+
+homepage = 'https://llvm.org/docs/CommandGuide/lit.html'
+description = """lit is a portable tool for executing LLVM and Clang style test suites, summarizing their results, and
+providing indication of failures."""
+
+toolchain = {'name': 'GCCcore', 'version': '15.2.0'}
+
+builddependencies = [
+    ('binutils', '2.45'),
+]
+
+dependencies = [
+    ('Python', '3.14.2'),
+]
+
+exts_list = [
+    ('ptyprocess', '0.7.0', {
+        'source_tmpl': '%(name)s-%(version)s-py2.py3-none-any.whl',
+        'checksums': ['4b41f3967fce3af57cc7e94b888626c18bf37a083e3651ca8feeb66d492fef35'],
+    }),
+    ('pexpect', '4.9.0', {
+        'checksums': ['ee7d41123f3c9911050ea2c2dac107568dc43b2d3b0c7557a33212c398ead30f'],
+    }),
+    (name, version, {
+        'checksums': ['47c174a186941ae830f04ded76a3444600be67d5e5fb8282c3783fba671c4edb'],
+    }),
+]
+
+sanity_check_commands = ['lit -h']
+
+moduleclass = 'tools'
diff --git a/easybuild/easyconfigs/p/psutil/psutil-7.2.1-GCCcore-15.2.0.eb b/easybuild/easyconfigs/p/psutil/psutil-7.2.1-GCCcore-15.2.0.eb
new file mode 100644
index 000000000000..797176652a7e
--- /dev/null
+++ b/easybuild/easyconfigs/p/psutil/psutil-7.2.1-GCCcore-15.2.0.eb
@@ -0,0 +1,23 @@
+easyblock = 'PythonBundle'
+
+name = 'psutil'
+version = '7.2.1'
+
+homepage = 'https://github.com/giampaolo/psutil'
+description = """A cross-platform process and system utilities module for Python"""
+
+toolchain = {'name': 'GCCcore', 'version': '15.2.0'}
+
+builddependencies = [('binutils', '2.45')]
+
+dependencies = [('Python', '3.14.2')]
+
+exts_list = [
+    (name, version, {
+        'source_urls': ['https://github.com/giampaolo/psutil/archive'],
+        'sources': ['release-%(version)s.tar.gz'],
+        'checksums': ['221eca326a94fc0c6aff9cfe7b9e053b54bd72678f5006c6d930e8cb26f04b25'],
+    }),
+]
+
+moduleclass = 'lib'
diff --git a/easybuild/easyconfigs/z/Z3/Z3-4.15.4-GCCcore-15.2.0.eb b/easybuild/easyconfigs/z/Z3/Z3-4.15.4-GCCcore-15.2.0.eb
new file mode 100644
index 000000000000..9215b7ba955d
--- /dev/null
+++ b/easybuild/easyconfigs/z/Z3/Z3-4.15.4-GCCcore-15.2.0.eb
@@ -0,0 +1,48 @@
+easyblock = 'PythonBundle'
+
+name = 'Z3'
+version = '4.15.4'
+
+homepage = 'https://github.com/Z3Prover/z3'
+description = """Z3 is a theorem prover from Microsoft Research with support for bitvectors,
+booleans, arrays, floating point numbers, strings, and other data types. This
+module includes z3-solver, the Python interface of Z3.
+"""
+
+toolchain = {'name': 'GCCcore', 'version': '15.2.0'}
+
+builddependencies = [
+    ('binutils', '2.45'),
+    ('CMake', '4.2.1'),
+]
+
+dependencies = [
+    ('Python', '3.14.2'),
+    ('GMP', '6.3.0'),
+]
+
+
+_fix_parallelism = """sed -i 's/str(multiprocessing.cpu_count())/"%(parallel)s"/' setup.py && """
+_enable_gmp = """sed -i "s/Z3_USE_LIB_GMP.*/Z3_USE_LIB_GMP' : True,/" setup.py && """
+
+exts_list = [
+    ('z3_solver', version + '.0', {
+        'modulename': 'z3',
+        'preinstallopts': _fix_parallelism + _enable_gmp,
+        'checksums': ['928c29b58c4eb62106da51c1914f6a4a55d0441f8f48a81b9da07950434a8946'],
+    }),
+]
+
+# make Z3 headers and libraries accessible in their usual location
+local_z3_site_path = "lib/python%(pyshortver)s/site-packages/%(namelower)s"
+postinstallcmds = [
+    'ln -s %s/include "%%(installdir)s/include"' % local_z3_site_path,
+    'cd "%%(installdir)s"; for lib in %s/lib/*; do ln -s ../$lib lib/$(basename $lib); done' % local_z3_site_path
+]
+
+sanity_check_paths = {
+    'files': ['bin/z3', 'include/z3_api.h', 'lib/libz3.' + SHLIB_EXT],
+    'dirs': ['include', 'lib/python%(pyshortver)s/site-packages'],
+}
+
+moduleclass = 'tools'