diff --git a/dev-ml/llvm/Manifest b/dev-ml/llvm/Manifest
index dabdc33c6ae5d..6651246b5d524 100644
--- a/dev-ml/llvm/Manifest
+++ b/dev-ml/llvm/Manifest
@@ -11,3 +11,4 @@ DIST llvm-project-19.1.7.src.tar.xz.sig 438 BLAKE2B 4015140f4ba77de45039bdbdfbaf
 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-23d0c7348aacdfcb145a69e533a14131bae830cc.tar.gz 237123683 BLAKE2B 6713c82809a9793510615f54c3ad9b8b1d2449939b0c48ab10acd1a0db43b712b229356173c90b514bc91c08e9b2be7f8e54f797661b9743ae8c3aaa9acee15f SHA512 de94ab38f1d46124638d6e0650142a1612db27871ffa339c56224aba94a77f8ae6eb8c68ad0a5ed3fe000d7bff309d324cdb66a095be3c8211abfe600659bf1a
+DIST llvm-project-814ac2e3735e52c1162ac495c24158e0ac256520.tar.gz 237400805 BLAKE2B 59cbf2f7f5c3c1c2c187c72a40b94b05b2d3286678f78764bc7555d75ead40d2fd60b1807bbe6470f012a5958d0466b1f6b2bc842bba36731e7697a79307532b SHA512 63f31f28b7f01b840d88bfa3ffc4107ccffc623b26c7d0dc3e720a864ce7ca907dcbdcfaec7e31a1711220528a89175334518711a83824c82389343c2e4008d7
diff --git a/dev-ml/llvm/llvm-21.0.0_pre20250614.ebuild b/dev-ml/llvm/llvm-21.0.0_pre20250614.ebuild
new file mode 100644
index 0000000000000..e28a14abee10a
--- /dev/null
+++ b/dev-ml/llvm/llvm-21.0.0_pre20250614.ebuild
@@ -0,0 +1,107 @@
+# 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 llvm.org llvm-utils python-any-r1
+
+DESCRIPTION="OCaml bindings for LLVM"
+HOMEPAGE="https://llvm.org/"
+
+LICENSE="Apache-2.0-with-LLVM-exceptions UoI-NCSA"
+SLOT="0/${PV}"
+IUSE="+debug test"
+RESTRICT="!test? ( test )"
+
+RDEPEND="
+	>=dev-lang/ocaml-4.00.0:0=
+	dev-ml/ocaml-ctypes:=
+	~llvm-core/llvm-${PV}:=[debug?]
+	!llvm-core/llvm[ocaml(-)]
+"
+
+DEPEND="
+	${RDEPEND}
+"
+BDEPEND="
+	${PYTHON_DEPS}
+	dev-lang/perl
+	dev-ml/findlib
+"
+
+LLVM_COMPONENTS=( llvm cmake third-party )
+LLVM_USE_TARGETS=llvm
+llvm.org_set_globals
+
+src_configure() {
+	llvm_prepend_path "${LLVM_MAJOR}"
+
+	local libdir=$(get_libdir)
+	local mycmakeargs=(
+		-DLLVM_LIBDIR_SUFFIX=${libdir#lib}
+
+		-DBUILD_SHARED_LIBS=OFF
+		-DLLVM_BUILD_LLVM_DYLIB=ON
+		-DLLVM_LINK_LLVM_DYLIB=ON
+		-DLLVM_OCAML_OUT_OF_TREE=ON
+
+		# cheap hack: LLVM combines both anyway, and the only difference
+		# is that the former list is explicitly verified at cmake time
+		-DLLVM_TARGETS_TO_BUILD=""
+		-DLLVM_EXPERIMENTAL_TARGETS_TO_BUILD="${LLVM_TARGETS// /;}"
+		-DLLVM_BUILD_TESTS=$(usex test)
+
+		# disable various irrelevant deps and settings
+		-DLLVM_ENABLE_FFI=OFF
+		-DLLVM_ENABLE_TERMINFO=OFF
+		-DHAVE_HISTEDIT_H=NO
+		-DLLVM_ENABLE_ASSERTIONS=$(usex debug)
+		-DLLVM_ENABLE_EH=ON
+		-DLLVM_ENABLE_RTTI=ON
+
+		-DLLVM_HOST_TRIPLE="${CHOST}"
+
+		-DPython3_EXECUTABLE="${PYTHON}"
+
+		# TODO: ocamldoc
+	)
+
+	use test && mycmakeargs+=(
+		-DLLVM_LIT_ARGS="$(get_lit_flags)"
+	)
+
+	# LLVM_ENABLE_ASSERTIONS=NO does not guarantee this for us, #614844
+	# also: custom rules for OCaml do not work for CPPFLAGS
+	use debug || local -x CFLAGS="${CFLAGS} -DNDEBUG"
+	cmake_src_configure
+
+	local llvm_libdir=$(llvm-config --libdir)
+	# an ugly hack; TODO: figure out a way to pass -L to ocaml...
+	cd "${BUILD_DIR}/${libdir}" || die
+	ln -s "${llvm_libdir}"/*.so . || die
+
+	if use test; then
+		local llvm_bindir=$(llvm-config --bindir)
+		# Force using system-installed tools.
+		sed -i -e "/llvm_tools_dir/s@\".*\"@\"${llvm_bindir}\"@" \
+			"${BUILD_DIR}"/test/lit.site.cfg.py || die
+	fi
+}
+
+src_compile() {
+	cmake_build ocaml_all
+}
+
+src_test() {
+	# respect TMPDIR!
+	local -x LIT_PRESERVES_TMP=1
+	cmake_build check-llvm-bindings-ocaml
+}
+
+src_install() {
+	DESTDIR="${D}" \
+	cmake -P "${BUILD_DIR}"/bindings/ocaml/cmake_install.cmake || die
+
+	dodoc bindings/ocaml/README.txt
+}