diff --git a/llvm-core/libclc/Manifest b/llvm-core/libclc/Manifest
index 392493c200e0c..d173631df2d39 100644
--- a/llvm-core/libclc/Manifest
+++ b/llvm-core/libclc/Manifest
@@ -15,3 +15,4 @@ DIST llvm-project-20.1.4.src.tar.xz.sig 566 BLAKE2B 1f0f057dedf938190554ca1a51d9
 DIST llvm-project-ac8fc09688e10e983b99224b5dc5cbbeeedb1879.tar.gz 231567089 BLAKE2B f7878f114c908b21d179854bc693716b34b963612c6b5172789a37cd21fa316720d4e9498bc7679058db3e822ed240bfdafd85bfd00154914d747d0c0ed1cb48 SHA512 4c39db8b22fa087ca96c3b4541ec77ba8a826a126b4e93b0650e59b3622b22b329f60fa3780dd4572fdece409fd5833eda473046d7547f6ee3ac8aadb8f2fc34
 DIST llvm-project-b9e32749d273a957e60170d6e7ef205fd1fb1834.tar.gz 232146799 BLAKE2B f7c02bf1e6b9958114f07827ff00264774a7ad54b51c6867d7e66d7c9a94a36fb84f371d7d30c2f094a0d539b565fb651786ed9e0641f2bea8d982073f1a8ac0 SHA512 2d81ead79c606e00549d5205584f1bd272e4d7adf4b376fdba19e7fb719710e80b00b22ee3500ab2b990178fa044ca9fcf45bd2063e62e6a217b11775bb3b163
 DIST llvm-project-d1e38eab95b07b422194427474521623916bbf29.tar.gz 232705423 BLAKE2B bf5200c2223d8cdf7c34c84876d8cfeb9429cb6535ced226b1bf9ab468b6401fe3da8759f0fc1ab3112927304c5f74db29b18be60fa961ce99471caa2c6a1f33 SHA512 8fae137725ad4eb0f5bab73895c65b34d1e36ea039c9fb3978c908ecc6023094d84919b97dc405b86e2dd32f585d87b29cee02293c8156d10a8371b516ca5e7a
+DIST llvm-project-fcb4bda9dcfcdb64d8b069e8416c75d7a1a62e52.tar.gz 233149231 BLAKE2B 95a7a012a1e747afcf83ace3785c8ef6a3e10f6075e59eb1c5b077cc9edae244b648f341bc0ac6a45b2afc8f7ffe130a90a741a04465523f30f8322566386703 SHA512 b46f0c90a1c56750cada24183ca382b267a2d2faa0db7d77a8bdd4e94e6303e57d565cf85447b3c0e0efdd3750efef1e10e8ce6f1fe8f1ae10ee31d25ddf3fb7
diff --git a/llvm-core/libclc/libclc-21.0.0_pre20250510.ebuild b/llvm-core/libclc/libclc-21.0.0_pre20250510.ebuild
new file mode 100644
index 0000000000000..e04a4c254a22b
--- /dev/null
+++ b/llvm-core/libclc/libclc-21.0.0_pre20250510.ebuild
@@ -0,0 +1,64 @@
+# Copyright 1999-2025 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+LLVM_COMPAT=( 21 )
+PYTHON_COMPAT=( python3_{10..13} )
+inherit cmake llvm.org llvm-r1 python-any-r1
+
+DESCRIPTION="OpenCL C library"
+HOMEPAGE="https://libclc.llvm.org/"
+
+LICENSE="Apache-2.0-with-LLVM-exceptions || ( MIT BSD )"
+SLOT="0"
+IUSE="+spirv video_cards_nvidia video_cards_r600 video_cards_radeonsi"
+
+BDEPEND="
+	${PYTHON_DEPS}
+	$(llvm_gen_dep '
+		llvm-core/clang:${LLVM_SLOT}
+		spirv? ( dev-util/spirv-llvm-translator:${LLVM_SLOT} )
+	')
+"
+
+LLVM_COMPONENTS=( libclc )
+llvm.org_set_globals
+
+pkg_setup() {
+	llvm-r1_pkg_setup
+	python-any-r1_pkg_setup
+}
+
+src_configure() {
+	local libclc_targets=(
+		"clspv--"
+		"clspv64--"
+	)
+
+	use spirv && libclc_targets+=(
+		"spirv-mesa3d-"
+		"spirv64-mesa3d-"
+	)
+	use video_cards_nvidia && libclc_targets+=(
+		"nvptx--"
+		"nvptx64--"
+		"nvptx--nvidiacl"
+		"nvptx64--nvidiacl"
+	)
+	use video_cards_r600 && libclc_targets+=(
+		"r600--"
+	)
+	use video_cards_radeonsi && libclc_targets+=(
+		"amdgcn--"
+		"amdgcn-mesa-mesa3d"
+		"amdgcn--amdhsa"
+	)
+	[[ ${#libclc_targets[@]} ]] || die "libclc target missing!"
+
+	libclc_targets=${libclc_targets[*]}
+	local mycmakeargs=(
+		-DLIBCLC_TARGETS_TO_BUILD="${libclc_targets// /;}"
+	)
+	cmake_src_configure
+}