Only recalculate DFS Numbers if invalid. Invalidate DFS numbers on reset. Add unit test to verify recalculation

llvm-svn: 234933

1 files changed, 28 insertions, 0 deletions

diff --git a/llvm/unittests/IR/DominatorTreeTest.cpp b/llvm/unittests/IR/DominatorTreeTest.cpp
index 287a9448454..6a5838e693a 100644
--- a/llvm/unittests/IR/DominatorTreeTest.cpp
+++ b/llvm/unittests/IR/DominatorTreeTest.cpp
@@ -10,6 +10,7 @@
 #include "llvm/IR/Dominators.h"
 #include "llvm/Analysis/PostDominators.h"
 #include "llvm/AsmParser/Parser.h"
+#include "llvm/IR/Constants.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
@@ -174,6 +175,33 @@ namespace llvm {
         EXPECT_EQ(DominatedBBs.size(), 0UL);
         EXPECT_EQ(PostDominatedBBs.size(), 0UL);
 
+        // Check DFS Numbers before
+        EXPECT_EQ(DT->getNode(BB0)->getDFSNumIn(), 0UL);
+        EXPECT_EQ(DT->getNode(BB0)->getDFSNumOut(), 7UL);
+        EXPECT_EQ(DT->getNode(BB1)->getDFSNumIn(), 1UL);
+        EXPECT_EQ(DT->getNode(BB1)->getDFSNumOut(), 2UL);
+        EXPECT_EQ(DT->getNode(BB2)->getDFSNumIn(), 5UL);
+        EXPECT_EQ(DT->getNode(BB2)->getDFSNumOut(), 6UL);
+        EXPECT_EQ(DT->getNode(BB4)->getDFSNumIn(), 3UL);
+        EXPECT_EQ(DT->getNode(BB4)->getDFSNumOut(), 4UL);
+
+        // Reattach block 3 to block 1 and recalculate
+        BB1->getTerminator()->eraseFromParent();
+        BranchInst::Create(BB4, BB3, ConstantInt::getTrue(F.getContext()), BB1);
+        DT->recalculate(F);
+
+        // Check DFS Numbers after
+        EXPECT_EQ(DT->getNode(BB0)->getDFSNumIn(), 0UL);
+        EXPECT_EQ(DT->getNode(BB0)->getDFSNumOut(), 9UL);
+        EXPECT_EQ(DT->getNode(BB1)->getDFSNumIn(), 1UL);
+        EXPECT_EQ(DT->getNode(BB1)->getDFSNumOut(), 4UL);
+        EXPECT_EQ(DT->getNode(BB2)->getDFSNumIn(), 7UL);
+        EXPECT_EQ(DT->getNode(BB2)->getDFSNumOut(), 8UL);
+        EXPECT_EQ(DT->getNode(BB3)->getDFSNumIn(), 2UL);
+        EXPECT_EQ(DT->getNode(BB3)->getDFSNumOut(), 3UL);
+        EXPECT_EQ(DT->getNode(BB4)->getDFSNumIn(), 5UL);
+        EXPECT_EQ(DT->getNode(BB4)->getDFSNumOut(), 6UL);
+
         return false;
       }
       void getAnalysisUsage(AnalysisUsage &AU) const override {