diff --git a/llvm-runtimes/offload/Manifest b/llvm-runtimes/offload/Manifest
index 921bc0f7067ac..22a0d9cf6c6fb 100644
--- a/llvm-runtimes/offload/Manifest
+++ b/llvm-runtimes/offload/Manifest
@@ -4,4 +4,6 @@ DIST llvm-project-20.1.7.src.tar.xz 147245448 BLAKE2B f7c57d1eba4e97e875b624dec3
 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-21.1.0-rc1.src.tar.xz 158955624 BLAKE2B 6a33d48f41f92cd8731011678afdf4c6f6a4581af04483626c511d1c9410d62788eb660e05cdfe418085509b576c29eec5bb07ae7ddc993e9931287657c11e03 SHA512 7ab3d1bb49bd3c5c9c1490cd865fdef027c25d64bb7f6a2a16c11c311670d08b7a214323ae4781aa0f49973deb0039ebea9d04887089df8dedf65080acdfc871
+DIST llvm-project-21.1.0-rc1.src.tar.xz.sig 438 BLAKE2B d3736b7f4bb6133e542fb3f52d1b76acc2920558e61bbbeeec6e5b7639ca54e229803b27baa4aedd2134c11fb4439064ac36e90c8c1831a503dd1754efee8da6 SHA512 6b9565f270fae4e534a160916bbd01ccd0e1295bf17df13f3be05bed4f058c0e935ba7385aba74a195d3a13868d81f2a0cf4be966b216fc6d7b56002f33eb4a0
 DIST llvm-project-b6313b381ac0e83012ea11b4549cd8cb39b686d2.tar.gz 242588863 BLAKE2B 81e7db20b849ce7a5c7c6b03d1e62a2e225eb68473509baf0adc9e74a2f759d251b61b018528d5db93f77b65ac355a71ede81bec7e97f9c71a41f34a5d8625bd SHA512 258b99ef79d7efd4ec58d6a5370969b8032149f05fea4dfa841398ed59a550219f4223cd79581bc6fc4428dd9b09f44abf9f5369348831f463b9eb401a614d61
diff --git a/llvm-runtimes/offload/offload-21.1.0_rc1.ebuild b/llvm-runtimes/offload/offload-21.1.0_rc1.ebuild
new file mode 100644
index 0000000000000..5f4ab86974966
--- /dev/null
+++ b/llvm-runtimes/offload/offload-21.1.0_rc1.ebuild
@@ -0,0 +1,145 @@
+# 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 crossdev flag-o-matic llvm.org python-any-r1
+inherit toolchain-funcs
+
+DESCRIPTION="OpenMP offloading support"
+HOMEPAGE="https://openmp.llvm.org"
+
+LICENSE="Apache-2.0-with-LLVM-exceptions || ( UoI-NCSA MIT )"
+SLOT="0/${LLVM_SOABI}"
+IUSE="+clang +debug ompt test llvm_targets_AMDGPU llvm_targets_NVPTX"
+REQUIRED_USE="
+	llvm_targets_AMDGPU? ( clang )
+	llvm_targets_NVPTX? ( clang )
+"
+RESTRICT="!test? ( test )"
+
+RDEPEND="
+	dev-libs/libffi:=
+	~llvm-core/llvm-${PV}
+	~llvm-runtimes/openmp-${PV}[ompt?]
+	llvm_targets_AMDGPU? ( dev-libs/rocr-runtime:= )
+"
+DEPEND="
+	${RDEPEND}
+"
+# tests:
+# - dev-python/lit provides the test runner
+# - llvm-core/llvm provide test utils (e.g. FileCheck)
+# - llvm-core/clang provides the compiler to run tests
+BDEPEND="
+	dev-lang/perl
+	virtual/pkgconfig
+	clang? ( llvm-core/clang )
+	llvm_targets_AMDGPU? ( llvm-core/clang[llvm_targets_AMDGPU] )
+	llvm_targets_NVPTX? ( llvm-core/clang[llvm_targets_NVPTX] )
+	test? (
+		$(python_gen_any_dep '
+			dev-python/lit[${PYTHON_USEDEP}]
+		')
+		llvm-core/clang
+	)
+"
+
+LLVM_COMPONENTS=( offload cmake runtimes/cmake libc )
+LLVM_TEST_COMPONENTS=( openmp/cmake )
+llvm.org_set_globals
+
+pkg_pretend() {
+	if [[ ${LLVM_ALLOW_GPU_TESTING} ]]; then
+		ewarn "LLVM_ALLOW_GPU_TESTING set.  This package will run tests against your"
+		ewarn "GPU if it is supported.  Note that these tests may be flaky, fail or"
+		ewarn "hang, or even cause your GPU to crash (requiring a reboot)."
+	fi
+}
+
+python_check_deps() {
+	python_has_version "dev-python/lit[${PYTHON_USEDEP}]"
+}
+
+pkg_setup() {
+	if use test; then
+		python-any-r1_pkg_setup
+	fi
+}
+
+src_configure() {
+	if use clang && ! is_crosspkg; then
+		# Only do this conditionally to allow overriding with
+		# e.g. CC=clang-13 in case of breakage
+		if ! tc-is-clang ; then
+			local -x CC=${CHOST}-clang
+			local -x CXX=${CHOST}-clang++
+		fi
+
+		strip-unsupported-flags
+	fi
+
+	# LLVM_ENABLE_ASSERTIONS=NO does not guarantee this for us, #614844
+	use debug || local -x CPPFLAGS="${CPPFLAGS} -DNDEBUG"
+
+	local libdir="$(get_libdir)"
+	local ffi_cflags=$($(tc-getPKG_CONFIG) --cflags-only-I libffi)
+	local ffi_ldflags=$($(tc-getPKG_CONFIG) --libs-only-L libffi)
+	local plugins="host"
+	local build_devicertl=FALSE
+
+	if has "${CHOST%%-*}" aarch64 powerpc64le x86_64; then
+		if use llvm_targets_AMDGPU; then
+			plugins+=";amdgpu"
+			build_devicertl=TRUE
+		fi
+		if use llvm_targets_NVPTX; then
+			plugins+=";cuda"
+			build_devicertl=TRUE
+		fi
+	fi
+
+	local mycmakeargs=(
+		-DLLVM_ROOT="${ESYSROOT}/usr/lib/llvm/${LLVM_MAJOR}"
+
+		-DOFFLOAD_LIBDIR_SUFFIX="${libdir#lib}"
+		-DOFFLOAD_INCLUDE_TESTS=$(usex test)
+		-DLIBOMPTARGET_PLUGINS_TO_BUILD="${plugins}"
+		-DLIBOMPTARGET_OMPT_SUPPORT="$(usex ompt)"
+		-DLIBOMPTARGET_BUILD_DEVICERTL_BCLIB="${build_devicertl}"
+
+		# this breaks building static target libs
+		-DBUILD_SHARED_LIBS=OFF
+
+		-DFFI_INCLUDE_DIR="${ffi_cflags#-I}"
+		-DFFI_LIBRARY_DIR="${ffi_ldflags#-L}"
+		# force using shared libffi
+		-DFFI_STATIC_LIBRARIES=NO
+	)
+
+	[[ ! ${LLVM_ALLOW_GPU_TESTING} ]] && mycmakeargs+=(
+		# prevent trying to access the GPU
+		-DLIBOMPTARGET_AMDGPU_ARCH=LIBOMPTARGET_AMDGPU_ARCH-NOTFOUND
+		-DLIBOMPTARGET_NVPTX_ARCH=LIBOMPTARGET_NVPTX_ARCH-NOTFOUND
+	)
+	use test && mycmakeargs+=(
+		# this project does not use standard LLVM cmake macros
+		-DOPENMP_LLVM_LIT_EXECUTABLE="${EPREFIX}/usr/bin/lit"
+		-DOPENMP_LIT_ARGS="$(get_lit_flags)"
+
+		-DOPENMP_TEST_C_COMPILER="$(type -P "${CHOST}-clang")"
+		-DOPENMP_TEST_CXX_COMPILER="$(type -P "${CHOST}-clang++")"
+		# requires flang
+		-DOPENMP_TEST_Fortran_COMPILER=
+	)
+
+	cmake_src_configure
+}
+
+src_test() {
+	# respect TMPDIR!
+	local -x LIT_PRESERVES_TMP=1
+
+	cmake_build check-offload
+}