diff --git a/dev-qt/qttools/qttools-6.6.9999.ebuild b/dev-qt/qttools/qttools-6.6.9999.ebuild
index 9f6085643a944..49dfe820f8ace 100644
--- a/dev-qt/qttools/qttools-6.6.9999.ebuild
+++ b/dev-qt/qttools/qttools-6.6.9999.ebuild
@@ -3,7 +3,9 @@
 
 EAPI=8
 
-inherit desktop llvm optfeature qt6-build
+LLVM_COMPAT=( {15..18} )
+LLVM_OPTIONAL=1
+inherit desktop llvm-r1 optfeature qt6-build
 
 DESCRIPTION="Qt Tools Collection"
 
@@ -20,6 +22,7 @@ IUSE="
 # if not enabled (e.g. linguist gives lrelease but not the GUI linguist6)
 REQUIRED_USE="
 	assistant? ( widgets )
+	clang? ( ${LLVM_REQUIRED_USE} )
 	designer? ( qml widgets )
 	distancefieldgenerator? ( qml widgets )
 	pixeltool? ( widgets )
@@ -31,11 +34,15 @@ REQUIRED_USE="
 # and 3rdparty/ tries to FetchContent gtest)
 RESTRICT="test"
 
-LLVM_MAX_SLOT=17
 RDEPEND="
 	~dev-qt/qtbase-${PV}:6[network,widgets?]
 	assistant? ( ~dev-qt/qtbase-${PV}:6[sql,sqlite] )
-	clang? ( <sys-devel/clang-$((LLVM_MAX_SLOT+1)):= )
+	clang? (
+		$(llvm_gen_dep '
+			sys-devel/clang:${LLVM_SLOT}
+			sys-devel/llvm:${LLVM_SLOT}
+		')
+	)
 	designer? (
 		~dev-qt/qtbase-${PV}:6[xml,zstd=]
 		zstd? ( app-arch/zstd:= )
@@ -52,12 +59,8 @@ DEPEND="
 	)
 "
 
-llvm_check_deps() {
-	has_version -d "sys-devel/clang:${LLVM_SLOT}"
-}
-
 pkg_setup() {
-	use clang && llvm_pkg_setup
+	use clang && llvm-r1_pkg_setup
 }
 
 src_configure() {
diff --git a/dev-qt/qttools/qttools-6.7.9999.ebuild b/dev-qt/qttools/qttools-6.7.9999.ebuild
index 2a9817bfe0289..99231843045d0 100644
--- a/dev-qt/qttools/qttools-6.7.9999.ebuild
+++ b/dev-qt/qttools/qttools-6.7.9999.ebuild
@@ -3,7 +3,9 @@
 
 EAPI=8
 
-inherit desktop llvm optfeature qt6-build
+LLVM_COMPAT=( {15..18} ) # see .cmake.conf for minimum
+LLVM_OPTIONAL=1
+inherit desktop llvm-r1 optfeature qt6-build
 
 DESCRIPTION="Qt Tools Collection"
 
@@ -20,6 +22,7 @@ IUSE="
 # if not enabled (e.g. linguist gives lrelease but not the GUI linguist6)
 REQUIRED_USE="
 	assistant? ( widgets )
+	clang? ( ${LLVM_REQUIRED_USE} )
 	designer? ( qml widgets )
 	distancefieldgenerator? ( qml widgets )
 	pixeltool? ( widgets )
@@ -31,14 +34,14 @@ REQUIRED_USE="
 # and 3rdparty/ tries to FetchContent gtest)
 RESTRICT="test"
 
-QTTOOLS_LLVM_SLOTS=({17..15}) # QDOC_MINIMUM_CLANG_VERSION
-LLVM_MAX_SLOT=${QTTOOLS_LLVM_SLOTS[0]}
 RDEPEND="
 	~dev-qt/qtbase-${PV}:6[network,widgets?]
 	assistant? ( ~dev-qt/qtbase-${PV}:6[sql,sqlite] )
 	clang? (
-		<sys-devel/clang-$((LLVM_MAX_SLOT+1)):=
-		|| ( $(printf "sys-devel/clang:%d " "${QTTOOLS_LLVM_SLOTS[@]}") )
+		$(llvm_gen_dep '
+			sys-devel/clang:${LLVM_SLOT}
+			sys-devel/llvm:${LLVM_SLOT}
+		')
 	)
 	designer? (
 		~dev-qt/qtbase-${PV}:6[xml,zstd=]
@@ -56,12 +59,8 @@ DEPEND="
 	)
 "
 
-llvm_check_deps() {
-	has_version -d "sys-devel/clang:${LLVM_SLOT}"
-}
-
 pkg_setup() {
-	use clang && llvm_pkg_setup
+	use clang && llvm-r1_pkg_setup
 }
 
 src_configure() {
diff --git a/dev-qt/qttools/qttools-6.9999.ebuild b/dev-qt/qttools/qttools-6.9999.ebuild
index 2a9817bfe0289..99231843045d0 100644
--- a/dev-qt/qttools/qttools-6.9999.ebuild
+++ b/dev-qt/qttools/qttools-6.9999.ebuild
@@ -3,7 +3,9 @@
 
 EAPI=8
 
-inherit desktop llvm optfeature qt6-build
+LLVM_COMPAT=( {15..18} ) # see .cmake.conf for minimum
+LLVM_OPTIONAL=1
+inherit desktop llvm-r1 optfeature qt6-build
 
 DESCRIPTION="Qt Tools Collection"
 
@@ -20,6 +22,7 @@ IUSE="
 # if not enabled (e.g. linguist gives lrelease but not the GUI linguist6)
 REQUIRED_USE="
 	assistant? ( widgets )
+	clang? ( ${LLVM_REQUIRED_USE} )
 	designer? ( qml widgets )
 	distancefieldgenerator? ( qml widgets )
 	pixeltool? ( widgets )
@@ -31,14 +34,14 @@ REQUIRED_USE="
 # and 3rdparty/ tries to FetchContent gtest)
 RESTRICT="test"
 
-QTTOOLS_LLVM_SLOTS=({17..15}) # QDOC_MINIMUM_CLANG_VERSION
-LLVM_MAX_SLOT=${QTTOOLS_LLVM_SLOTS[0]}
 RDEPEND="
 	~dev-qt/qtbase-${PV}:6[network,widgets?]
 	assistant? ( ~dev-qt/qtbase-${PV}:6[sql,sqlite] )
 	clang? (
-		<sys-devel/clang-$((LLVM_MAX_SLOT+1)):=
-		|| ( $(printf "sys-devel/clang:%d " "${QTTOOLS_LLVM_SLOTS[@]}") )
+		$(llvm_gen_dep '
+			sys-devel/clang:${LLVM_SLOT}
+			sys-devel/llvm:${LLVM_SLOT}
+		')
 	)
 	designer? (
 		~dev-qt/qtbase-${PV}:6[xml,zstd=]
@@ -56,12 +59,8 @@ DEPEND="
 	)
 "
 
-llvm_check_deps() {
-	has_version -d "sys-devel/clang:${LLVM_SLOT}"
-}
-
 pkg_setup() {
-	use clang && llvm_pkg_setup
+	use clang && llvm-r1_pkg_setup
 }
 
 src_configure() {