diff --git a/llvm-runtimes/libcxx/Manifest b/llvm-runtimes/libcxx/Manifest
index af85d17aaef6f..589d8c295fdcc 100644
--- a/llvm-runtimes/libcxx/Manifest
+++ b/llvm-runtimes/libcxx/Manifest
@@ -12,5 +12,7 @@ DIST llvm-project-19.1.7.src.tar.xz 141249332 BLAKE2B 1259ed7f9aca7b35e89d818bef
 DIST llvm-project-19.1.7.src.tar.xz.sig 438 BLAKE2B 4015140f4ba77de45039bdbdfbaf6f30e75705123d067ea97175d91d7a5b6a75008df01d99ae7aa16aaa3b101f3f41e38d01f04158f95a261d617b3ede0254cd SHA512 195797b06ac80a742e0ccbc03a50dc06dd2e04377d783d5474e3e72c5a75203b60292b047929312a411d22b137a239943fba414a4d136a2be14cbff978eb6bda
 DIST llvm-project-20.1.7.src.tar.xz 147245448 BLAKE2B f7c57d1eba4e97e875b624dec3fb1b261a0203de7200366de5b3edcfbca2a170c41df46e91cd9cb78ae2af66120aef95334f5eb9628a1489e921c6bdf4cccfe8 SHA512 c2dbf6a468a8152409db7ff52902ecf8768a1d0328e386999f4f3672613903e1c10bddbba66b8553a6222952f8edb66266947f1fb21d0b09ae741e6249b6d1fa
 DIST llvm-project-20.1.7.src.tar.xz.sig 566 BLAKE2B 72ce2a18c211cfce9581a9e3e71f1c55cf18672aa355267581220e1a89e3327f9e16107970b69bb8f10f390baa5e286487bdc4cc0a7d9155ec13a4977cd3f472 SHA512 eff885059d547f57b98bda1fc9631f716ca6c650cd48203d9ed5443a6afb9a2d4d91d3f5c8618e307c0a44b3040bce61fdc6bce965073adc537655755d9f2112
+DIST llvm-project-20.1.8.src.tar.xz 147242952 BLAKE2B 7657ac0b26acc5affb1bfc91b912ade3191c5d77f3979d5a80d5f6ce52f56a7d1c448bd257398390bf10838f02faa6f3ece37a7327cced69d165ec2e2e699316 SHA512 f330e72e6a1da468569049437cc0ba7a41abb816ccece7367189344f7ebfef730f4788ac7af2bef0aa8a49341c15ab1d31e941ffa782f264d11fe0dc05470773
+DIST llvm-project-20.1.8.src.tar.xz.sig 566 BLAKE2B 85beedfcff1195a974fab2c667b9efd4b715b3480c1b44b1b887fe32c69f72aca0d3b8fb276c03b6cc5a866622f669047aeee5ccb976640b4008ccd31dce77a4 SHA512 d74369bdb4d1b82775161ea53c9c5f3a23ce810f4df5ff617123023f9d8ce720e7d6ecc9e17f8ebd39fd9e7a9de79560abdf2ffe73bcb907a43148d43665d619
 DIST llvm-project-814ac2e3735e52c1162ac495c24158e0ac256520.tar.gz 237400805 BLAKE2B 59cbf2f7f5c3c1c2c187c72a40b94b05b2d3286678f78764bc7555d75ead40d2fd60b1807bbe6470f012a5958d0466b1f6b2bc842bba36731e7697a79307532b SHA512 63f31f28b7f01b840d88bfa3ffc4107ccffc623b26c7d0dc3e720a864ce7ca907dcbdcfaec7e31a1711220528a89175334518711a83824c82389343c2e4008d7
 DIST llvm-project-e34e02128ec5eb89e36a8f0f7307dcbcfecabbee.tar.gz 238210997 BLAKE2B 80ce4689e3c71a413e36645cdc83590f3492ac3ee39b8bf8844ec50d0b68f40da4c19a7f284625e3550eb78a90d433e74092b5639bcebadf0e0220c36b111cb3 SHA512 5c1ab21b242d1ba62172ae6268a126fd1b049f85b039434b4ff28b0411ec60d46e96e05560b9b85d0420494afdd573b4043999cb34ace508a48f763d4eb5b7aa
diff --git a/llvm-runtimes/libcxx/libcxx-20.1.8.ebuild b/llvm-runtimes/libcxx/libcxx-20.1.8.ebuild
new file mode 100644
index 0000000000000..a5d900551442e
--- /dev/null
+++ b/llvm-runtimes/libcxx/libcxx-20.1.8.ebuild
@@ -0,0 +1,209 @@
+# Copyright 1999-2025 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+PYTHON_COMPAT=( python3_{11..14} )
+inherit cmake-multilib flag-o-matic llvm.org llvm-utils python-any-r1
+inherit toolchain-funcs
+
+DESCRIPTION="New implementation of the C++ standard library, targeting C++11"
+HOMEPAGE="https://libcxx.llvm.org/"
+
+LICENSE="Apache-2.0-with-LLVM-exceptions || ( UoI-NCSA MIT )"
+SLOT="0"
+KEYWORDS="~amd64 ~arm ~arm64 ~loong ~riscv ~sparc ~x86 ~arm64-macos ~x64-macos"
+IUSE="+clang +libcxxabi +static-libs test"
+REQUIRED_USE="test? ( clang )"
+RESTRICT="!test? ( test )"
+
+RDEPEND="
+	libcxxabi? (
+		~llvm-runtimes/libcxxabi-${PV}[static-libs?,${MULTILIB_USEDEP}]
+	)
+	!libcxxabi? ( >=sys-devel/gcc-4.7:=[cxx] )
+"
+DEPEND="
+	${RDEPEND}
+	llvm-core/llvm:${LLVM_MAJOR}
+"
+BDEPEND="
+	clang? (
+		llvm-core/clang:${LLVM_MAJOR}
+	)
+	!test? (
+		${PYTHON_DEPS}
+	)
+	test? (
+		dev-debug/gdb[python]
+		$(python_gen_any_dep 'dev-python/lit[${PYTHON_USEDEP}]')
+	)
+"
+
+LLVM_COMPONENTS=(
+	runtimes libcxx{,abi} libc llvm/{cmake,utils/llvm-lit} cmake
+)
+llvm.org_set_globals
+
+python_check_deps() {
+	use test || return 0
+	python_has_version "dev-python/lit[${PYTHON_USEDEP}]"
+}
+
+pkg_setup() {
+	python-any-r1_pkg_setup
+
+	if ! use libcxxabi && ! tc-is-gcc ; then
+		eerror "To build ${PN} against libsupc++, you have to use gcc. Other"
+		eerror "compilers are not supported. Please set CC=gcc and CXX=g++"
+		eerror "and try again."
+		die
+	fi
+}
+
+test_compiler() {
+	$(tc-getCXX) ${CXXFLAGS} ${LDFLAGS} "${@}" -o /dev/null -x c++ - \
+		<<<'int main() { return 0; }' &>/dev/null
+}
+
+src_configure() {
+	llvm_prepend_path "${LLVM_MAJOR}"
+
+	# note: we need to do this before multilib kicks in since it will
+	# alter the CHOST
+	local cxxabi cxxabi_incs
+	if use libcxxabi; then
+		cxxabi=system-libcxxabi
+		cxxabi_incs="${EPREFIX}/usr/include/c++/v1"
+	else
+		local gcc_inc="${EPREFIX}/usr/lib/gcc/${CHOST}/$(gcc-fullversion)/include/g++-v$(gcc-major-version)"
+		cxxabi=libsupc++
+		cxxabi_incs="${gcc_inc};${gcc_inc}/${CHOST}"
+	fi
+
+	multilib-minimal_src_configure
+}
+
+multilib_src_configure() {
+	if use clang; then
+		local -x CC=${CHOST}-clang
+		local -x CXX=${CHOST}-clang++
+		strip-unsupported-flags
+	fi
+
+	# link to compiler-rt
+	local use_compiler_rt=OFF
+	[[ $(tc-get-c-rtlib) == compiler-rt ]] && use_compiler_rt=ON
+
+	# bootstrap: cmake is unhappy if compiler can't link to stdlib
+	local nolib_flags=( -nodefaultlibs -lc )
+	if ! test_compiler; then
+		if test_compiler "${nolib_flags[@]}"; then
+			local -x LDFLAGS="${LDFLAGS} ${nolib_flags[*]}"
+			ewarn "${CXX} seems to lack runtime, trying with ${nolib_flags[*]}"
+		fi
+	fi
+
+	local libdir=$(get_libdir)
+	local mycmakeargs=(
+		-DCMAKE_CXX_COMPILER_TARGET="${CHOST}"
+		-DPython3_EXECUTABLE="${PYTHON}"
+		-DLLVM_ENABLE_RUNTIMES=libcxx
+		-DLLVM_INCLUDE_TESTS=OFF
+		-DLLVM_LIBDIR_SUFFIX=${libdir#lib}
+
+		-DLIBCXX_ENABLE_SHARED=ON
+		-DLIBCXX_ENABLE_STATIC=$(usex static-libs)
+		-DLIBCXX_CXX_ABI=${cxxabi}
+		-DLIBCXX_CXX_ABI_INCLUDE_PATHS=${cxxabi_incs}
+		# we're using our own mechanism for generating linker scripts
+		-DLIBCXX_ENABLE_ABI_LINKER_SCRIPT=OFF
+		-DLIBCXX_HAS_MUSL_LIBC=$(llvm_cmake_use_musl)
+		-DLIBCXX_INCLUDE_BENCHMARKS=OFF
+		-DLIBCXX_INCLUDE_TESTS=$(usex test)
+		-DLIBCXX_INSTALL_MODULES=ON
+		-DLIBCXX_USE_COMPILER_RT=${use_compiler_rt}
+		# this is broken with standalone builds, and also meaningless
+		-DLIBCXXABI_USE_LLVM_UNWINDER=OFF
+	)
+
+	if use test; then
+		mycmakeargs+=(
+			-DLLVM_EXTERNAL_LIT="${EPREFIX}/usr/bin/lit"
+			-DLLVM_LIT_ARGS="$(get_lit_flags)"
+			-DPython3_EXECUTABLE="${PYTHON}"
+		)
+	fi
+	cmake_src_configure
+}
+
+multilib_src_compile() {
+	cmake_src_compile
+	if [[ ${CHOST} != *-darwin* ]] ; then
+		gen_shared_ldscript
+		use static-libs && gen_static_ldscript
+	fi
+}
+
+multilib_src_test() {
+	local -x LIT_PRESERVES_TMP=1
+	cmake_build install-cxx-test-suite-prefix
+	cp "${BUILD_DIR}"/{lib,libcxx/test-suite-install/$(get_libdir)}/libc++_shared.so || die
+	if use static-libs; then
+		cp "${BUILD_DIR}"/{lib,libcxx/test-suite-install/$(get_libdir)}/libc++_static.a || die
+	fi
+	cmake_build check-cxx
+}
+
+multilib_src_install() {
+	cmake_src_install
+	# since we've replaced libc++.{a,so} with ldscripts, now we have to
+	# install the extra symlinks
+	if [[ ${CHOST} != *-darwin* ]] ; then
+		dolib.so lib/libc++_shared.so
+		use static-libs && dolib.a lib/libc++_static.a
+	fi
+}
+
+# Usage: deps
+gen_ldscript() {
+	local output_format
+	output_format=$($(tc-getCC) ${CFLAGS} ${LDFLAGS} -Wl,--verbose 2>&1 | sed -n 's/^OUTPUT_FORMAT("\([^"]*\)",.*/\1/p')
+	[[ -n ${output_format} ]] && output_format="OUTPUT_FORMAT ( ${output_format} )"
+
+	cat <<-END_LDSCRIPT
+/* GNU ld script
+   Include missing dependencies
+*/
+${output_format}
+GROUP ( $@ )
+END_LDSCRIPT
+}
+
+gen_static_ldscript() {
+	# Move it first.
+	mv lib/libc++{,_static}.a || die
+	# Generate libc++.a ldscript for inclusion of its dependencies so that
+	# clang++ -stdlib=libc++ -static works out of the box.
+	local deps=(
+		libc++_static.a
+		$(usex libcxxabi libc++abi.a libsupc++.a)
+	)
+	# On Linux/glibc it does not link without libpthread or libdl. It is
+	# fine on FreeBSD.
+	use elibc_glibc && deps+=( libpthread.a libdl.a )
+
+	gen_ldscript "${deps[*]}" > lib/libc++.a || die
+}
+
+gen_shared_ldscript() {
+	# Move it first.
+	mv lib/libc++{,_shared}.so || die
+	local deps=(
+		libc++_shared.so
+		# libsupc++ doesn't have a shared version
+		$(usex libcxxabi libc++abi.so libsupc++.a)
+	)
+
+	gen_ldscript "${deps[*]}" > lib/libc++.so || die
+}