Index: clang/lib/Sema/SemaOpenMP.cpp
===================================================================
--- clang/lib/Sema/SemaOpenMP.cpp
+++ clang/lib/Sema/SemaOpenMP.cpp
@@ -6683,6 +6683,7 @@
     D.setFunctionDefinitionKind(FunctionDefinitionKind::Declaration);
     Decl *BaseD = HandleDeclarator(S, D, TemplateParamLists);
     BaseD->setImplicit(true);
+    BaseD->setIsUsed();
     if (auto *BaseTemplD = dyn_cast<FunctionTemplateDecl>(BaseD))
       Bases.push_back(BaseTemplD->getTemplatedDecl());
     else
Index: clang/test/OpenMP/declare_variant.cpp
===================================================================
--- /dev/null
+++ clang/test/OpenMP/declare_variant.cpp
@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -fopenmp -verify %s
+
+// expected-no-diagnostics
+
+#pragma omp begin declare variant match(device = {kind(host)})
+static void foo(){};
+#pragma omp end declare variant
+
+int main() {
+  foo();
+
+  return 0;
+}