diff --git a/sci-electronics/ghdl/Manifest b/sci-electronics/ghdl/Manifest
index a6d889450929a..c435f58f6dca0 100644
--- a/sci-electronics/ghdl/Manifest
+++ b/sci-electronics/ghdl/Manifest
@@ -1 +1,2 @@
 DIST ghdl-3.0.0.tar.gz 7160245 BLAKE2B 685d8976db48dd6d7074540ff24fae11e8d75f2b0e91de3095b356c9ed1e8dd762c486b7fb1df5a874a653181c6d4f4be4f8e3f5881d10db941c467a95590f45 SHA512 11b638d0ae757ce2e247ab438c15a8f5cd78c3a025ba6272aa05df548d2a7276c25dbbf83b846284ded8c9864eca3dcdb8342cb532faecd01e7cefaada524ab0
+DIST ghdl-4.0.0_pre20231218.tar.gz 7761842 BLAKE2B d5b3ae4c28b245881681695cee74eca1d69092d8089cb1ec042f42d26e62aa420ace8f04899023d98259d845ea89700d77c453b892c176d4d1b367ac7a8237a6 SHA512 6b9ac7221bee5b8ec2cc7971fbad5aff615839aa3c3170fa39079c68e65da8b4a8d60f5c53d9fa88146c9f865b0d8a059fd03358e20b660b6543cf1b0c0b0c84
diff --git a/sci-electronics/ghdl/files/ghdl-4.0.0_pre20231218-no-pyunit.patch b/sci-electronics/ghdl/files/ghdl-4.0.0_pre20231218-no-pyunit.patch
new file mode 100644
index 0000000000000..91cb22d6035af
--- /dev/null
+++ b/sci-electronics/ghdl/files/ghdl-4.0.0_pre20231218-no-pyunit.patch
@@ -0,0 +1,18 @@
+diff --git a/testsuite/testsuite.sh.orig b/testsuite/testsuite.sh
+index 0c1049f..52da6db 100755
+--- a/testsuite/testsuite.sh.orig
++++ b/testsuite/testsuite.sh
+@@ -130,9 +130,10 @@ do_test() {
+     pyunit)
+       # The Python Unit testsuite: regression testsuite for Python bindings to libghdl
+       # pyunit/dom fails with python 3.12
+-      gstart "[GHDL - test] pyunit"
+-      PYTHONPATH=$(pwd)/.. ${PYTHON:-python3} -m pytest -vsrA pyunit/lsp pyunit/libghdl
+-      gend
++      # gstart "[GHDL - test] pyunit"
++      # PYTHONPATH=$(pwd)/.. ${PYTHON:-python3} -m pytest -vsrA pyunit/lsp pyunit/libghdl
++      # gend
++      echo "Python Unit testsuite is disabled!"
+     ;;
+ 
+     vests)
diff --git a/sci-electronics/ghdl/ghdl-4.0.0_pre20231218.ebuild b/sci-electronics/ghdl/ghdl-4.0.0_pre20231218.ebuild
new file mode 100644
index 0000000000000..84be680e666c0
--- /dev/null
+++ b/sci-electronics/ghdl/ghdl-4.0.0_pre20231218.ebuild
@@ -0,0 +1,84 @@
+# Copyright 1999-2023 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+[[ "${PV}" = *_pre20231218 ]] && COMMIT=2135cbf1458bd1b8b8f42bda81222ab57bd66de6
+
+ADA_COMPAT=( gnat_2021 )
+LLVM_MAX_SLOT=17        # Check "configure" script for supported LLVM versions.
+
+inherit ada edo llvm toolchain-funcs
+
+DESCRIPTION="Open-source analyzer, compiler, and simulator for VHDL 2008/93/87"
+HOMEPAGE="https://ghdl.github.io/ghdl/
+	https://github.com/ghdl/ghdl/"
+
+if [[ "${PV}" == *9999* ]] ; then
+	inherit git-r3
+
+	EGIT_REPO_URI="https://github.com/ghdl/${PN}.git"
+else
+	SRC_URI="https://github.com/ghdl/${PN}/archive/${COMMIT}.tar.gz
+		-> ${P}.tar.gz"
+	S="${WORKDIR}/${PN}-${COMMIT}"
+
+	KEYWORDS="~amd64 ~x86"
+fi
+
+LICENSE="GPL-2+"
+SLOT="0"
+IUSE="llvm"
+REQUIRED_USE="${ADA_REQUIRED_USE}"
+
+RDEPEND="
+	${ADA_DEPS}
+	llvm? ( <sys-devel/llvm-$((${LLVM_MAX_SLOT} + 1)):= )
+"
+DEPEND="
+	${RDEPEND}
+"
+BDEPEND="
+	dev-util/patchelf
+"
+
+PATCHES=( "${FILESDIR}/${PN}-4.0.0_pre20231218-no-pyunit.patch" )
+
+pkg_setup() {
+	ada_pkg_setup
+
+	use llvm && llvm_pkg_setup
+}
+
+src_prepare() {
+	default
+
+	sed -i "s|ar rc|$(tc-getAR) rc|g" Makefile.in || die
+}
+
+src_configure() {
+	tc-export CC CXX
+
+	local -a myconf=(
+		--disable-werror
+
+		--libdir=$(get_libdir)
+		--prefix=/usr
+
+		--enable-libghdl
+		--enable-synth
+	)
+
+	if use llvm ; then
+		myconf+=( --with-llvm-config=llvm-config )
+	fi
+
+	# Not a autotools script!
+	edo sh ./configure "${myconf[@]}"
+}
+
+src_compile() {
+	default
+
+	patchelf --set-soname libghw.so lib/libghw.so || die
+}