[NFC] Add API for edge domination check in dom tree
diff --git a/llvm/unittests/IR/DominatorTreeTest.cpp b/llvm/unittests/IR/DominatorTreeTest.cpp
index 22d2003..66e1227 100644
--- a/llvm/unittests/IR/DominatorTreeTest.cpp
+++ b/llvm/unittests/IR/DominatorTreeTest.cpp
@@ -1020,3 +1020,54 @@
   EXPECT_TRUE(DT.verify());
 }
 
+TEST(DominatorTree, EdgeDomination) {
+  StringRef ModuleString = "define i32 @f(i1 %cond) {\n"
+                           " bb0:\n"
+                           "   br i1 %cond, label %bb1, label %bb2\n"
+                           " bb1:\n"
+                           "   br label %bb3\n"
+                           " bb2:\n"
+                           "   br label %bb3\n"
+                           " bb3:\n"
+                           "   ret i32 4"
+                           "}\n";
+
+  // Parse the module.
+  LLVMContext Context;
+  std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleString);
+
+  runWithDomTree(*M, "f",
+                 [&](Function &F, DominatorTree *DT, PostDominatorTree *PDT) {
+    Function::iterator FI = F.begin();
+
+    BasicBlock *BB0 = &*FI++;
+    BasicBlock *BB1 = &*FI++;
+    BasicBlock *BB2 = &*FI++;
+    BasicBlock *BB3 = &*FI++;
+
+    BasicBlockEdge E01(BB0, BB1);
+    BasicBlockEdge E02(BB0, BB2);
+    BasicBlockEdge E13(BB1, BB3);
+    BasicBlockEdge E23(BB2, BB3);
+
+    EXPECT_TRUE(DT->dominates(E01, E01));
+    EXPECT_FALSE(DT->dominates(E01, E02));
+    EXPECT_TRUE(DT->dominates(E01, E13));
+    EXPECT_FALSE(DT->dominates(E01, E23));
+
+    EXPECT_FALSE(DT->dominates(E02, E01));
+    EXPECT_TRUE(DT->dominates(E02, E02));
+    EXPECT_FALSE(DT->dominates(E02, E13));
+    EXPECT_TRUE(DT->dominates(E02, E23));
+
+    EXPECT_FALSE(DT->dominates(E13, E01));
+    EXPECT_FALSE(DT->dominates(E13, E02));
+    EXPECT_TRUE(DT->dominates(E13, E13));
+    EXPECT_FALSE(DT->dominates(E13, E23));
+
+    EXPECT_FALSE(DT->dominates(E23, E01));
+    EXPECT_FALSE(DT->dominates(E23, E02));
+    EXPECT_FALSE(DT->dominates(E23, E13));
+    EXPECT_TRUE(DT->dominates(E23, E23));
+  });
+}