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diff --git a/clang/unittests/Analysis/CFGDominatorTree.cpp b/clang/unittests/Analysis/CFGDominatorTree.cpp
new file mode 100644
index 00000000000..1df8c2f7d05
--- /dev/null
+++ b/clang/unittests/Analysis/CFGDominatorTree.cpp
@@ -0,0 +1,103 @@
+//===- unittests/Analysis/CFGDominatorTree.cpp - CFG tests ----------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "CFGBuildResult.h"
+#include "clang/Analysis/Analyses/Dominators.h"
+#include "gtest/gtest.h"
+
+namespace clang {
+namespace analysis {
+namespace {
+
+TEST(CFGDominatorTree, DomTree) {
+  const char *Code = R"(enum Kind {
+                          A
+                        };
+
+                        void f() {
+                          switch(Kind{}) {
+                          case A:
+                            break;
+                          }
+                        })";
+  BuildResult Result = BuildCFG(Code);
+  EXPECT_EQ(BuildResult::BuiltCFG, Result.getStatus());
+
+  //  [B3 (ENTRY)]  -> [B1] -> [B2] -> [B0 (EXIT)]
+  //                  switch  case A
+
+  CFG *cfg = Result.getCFG();
+
+  // Sanity checks.
+  EXPECT_EQ(cfg->size(), 4u);
+
+  CFGBlock *ExitBlock = *cfg->begin();
+  EXPECT_EQ(ExitBlock, &cfg->getExit());
+
+  CFGBlock *SwitchBlock = *(cfg->begin() + 1);
+
+  CFGBlock *CaseABlock = *(cfg->begin() + 2);
+
+  CFGBlock *EntryBlock = *(cfg->begin() + 3);
+  EXPECT_EQ(EntryBlock, &cfg->getEntry());
+
+  // Test the dominator tree.
+  CFGDomTree Dom;
+  Dom.buildDominatorTree(cfg);
+
+  EXPECT_TRUE(Dom.dominates(ExitBlock, ExitBlock));
+  EXPECT_FALSE(Dom.properlyDominates(ExitBlock, ExitBlock));
+  EXPECT_TRUE(Dom.dominates(CaseABlock, ExitBlock));
+  EXPECT_TRUE(Dom.dominates(SwitchBlock, ExitBlock));
+  EXPECT_TRUE(Dom.dominates(EntryBlock, ExitBlock));
+
+  EXPECT_TRUE(Dom.dominates(CaseABlock, CaseABlock));
+  EXPECT_FALSE(Dom.properlyDominates(CaseABlock, CaseABlock));
+  EXPECT_TRUE(Dom.dominates(SwitchBlock, CaseABlock));
+  EXPECT_TRUE(Dom.dominates(EntryBlock, CaseABlock));
+
+  EXPECT_TRUE(Dom.dominates(SwitchBlock, SwitchBlock));
+  EXPECT_FALSE(Dom.properlyDominates(SwitchBlock, SwitchBlock));
+  EXPECT_TRUE(Dom.dominates(EntryBlock, SwitchBlock));
+
+  EXPECT_TRUE(Dom.dominates(EntryBlock, EntryBlock));
+  EXPECT_FALSE(Dom.properlyDominates(EntryBlock, EntryBlock));
+
+  // Test the post dominator tree.
+
+  CFGPostDomTree PostDom;
+  PostDom.buildDominatorTree(cfg);
+
+  EXPECT_TRUE(PostDom.dominates(ExitBlock, EntryBlock));
+  EXPECT_TRUE(PostDom.dominates(CaseABlock, EntryBlock));
+  EXPECT_TRUE(PostDom.dominates(SwitchBlock, EntryBlock));
+  EXPECT_TRUE(PostDom.dominates(EntryBlock, EntryBlock));
+  EXPECT_FALSE(Dom.properlyDominates(EntryBlock, EntryBlock));
+
+  EXPECT_TRUE(PostDom.dominates(ExitBlock, SwitchBlock));
+  EXPECT_TRUE(PostDom.dominates(CaseABlock, SwitchBlock));
+  EXPECT_TRUE(PostDom.dominates(SwitchBlock, SwitchBlock));
+  EXPECT_FALSE(Dom.properlyDominates(SwitchBlock, SwitchBlock));
+
+  EXPECT_TRUE(PostDom.dominates(ExitBlock, CaseABlock));
+  EXPECT_TRUE(PostDom.dominates(CaseABlock, CaseABlock));
+  EXPECT_FALSE(Dom.properlyDominates(CaseABlock, CaseABlock));
+
+  EXPECT_TRUE(PostDom.dominates(ExitBlock, ExitBlock));
+  EXPECT_FALSE(Dom.properlyDominates(ExitBlock, ExitBlock));
+
+  // Tests for the post dominator tree's virtual root.
+  EXPECT_TRUE(PostDom.dominates(nullptr, EntryBlock));
+  EXPECT_TRUE(PostDom.dominates(nullptr, SwitchBlock));
+  EXPECT_TRUE(PostDom.dominates(nullptr, CaseABlock));
+  EXPECT_TRUE(PostDom.dominates(nullptr, ExitBlock));
+}
+
+} // namespace
+} // namespace analysis
+} // namespace clang