[llvm] r234933 - Only recalculate DFS Numbers if invalid. Invalidate DFS numbers on reset. Add unit test to verify recalculation

[Daniel Berlin]

Author: dannyb
Date: Tue Apr 14 14:49:26 2015
New Revision: 234933

URL: http://llvm.org/viewvc/llvm-project?rev=234933&view=rev
Log:
Only recalculate DFS Numbers if invalid. Invalidate DFS numbers on reset. Add unit test to verify recalculation

Modified:
    llvm/trunk/include/llvm/Support/GenericDomTree.h
    llvm/trunk/unittests/IR/DominatorTreeTest.cpp

Modified: llvm/trunk/include/llvm/Support/GenericDomTree.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/GenericDomTree.h?rev=234933&r1=234932&r2=234933&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/GenericDomTree.h (original)
+++ llvm/trunk/include/llvm/Support/GenericDomTree.h Tue Apr 14 14:49:26 2015
@@ -243,6 +243,8 @@ protected:
     this->Roots.clear();
     Vertex.clear();
     RootNode = nullptr;
+    DFSInfoValid = false;
+    SlowQueries = 0;
   }
 
   // NewBB is split and now it has one successor. Update dominator tree to
@@ -663,6 +665,12 @@ public:
   /// updateDFSNumbers - Assign In and Out numbers to the nodes while walking
   /// dominator tree in dfs order.
   void updateDFSNumbers() const {
+
+    if (DFSInfoValid) {
+      SlowQueries = 0;
+      return;
+    }
+
     unsigned DFSNum = 0;
 
     SmallVector<std::pair<const DomTreeNodeBase<NodeT> *,

Modified: llvm/trunk/unittests/IR/DominatorTreeTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/IR/DominatorTreeTest.cpp?rev=234933&r1=234932&r2=234933&view=diff
==============================================================================
--- llvm/trunk/unittests/IR/DominatorTreeTest.cpp (original)
+++ llvm/trunk/unittests/IR/DominatorTreeTest.cpp Tue Apr 14 14:49:26 2015
@@ -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 {