Update LoopSimplify to require and preserve DominatorTree only.

Now LoopSimplify does not require nor preserve ETForest.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37512 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 12 insertions, 3 deletions

diff --git a/lib/VMCore/Dominators.cpp b/lib/VMCore/Dominators.cpp
index fc5d6a63ca..32c435b2c6 100644
--- a/lib/VMCore/Dominators.cpp
+++ b/lib/VMCore/Dominators.cpp
@@ -316,14 +316,23 @@ void DominatorTreeBase::updateDFSNumbers()
     for (df_iterator<BasicBlock*> I = df_begin(Roots[i]),
            E = df_end(Roots[i]); I != E; ++I) {
       BasicBlock *BB = *I;
-      ETNode *ETN = getNode(BB)->getETNode();
-      if (ETN && !ETN->hasFather())
-        ETN->assignDFSNumber(dfsnum);    
+      DomTreeNode *BBNode = getNode(BB);
+      if (BBNode) {
+        ETNode *ETN = BBNode->getETNode();
+        if (ETN && !ETN->hasFather())
+          ETN->assignDFSNumber(dfsnum);
+      }
   }
   SlowQueries = 0;
   DFSInfoValid = true;
 }
 
+/// isReachableFromEntry - Return true if A is dominated by the entry
+/// block of the function containing it.
+const bool DominatorTreeBase::isReachableFromEntry(BasicBlock* A) {
+  return dominates(&A->getParent()->getEntryBlock(), A);
+}
+
 // dominates - Return true if A dominates B. THis performs the
 // special checks necessary if A and B are in the same basic block.
 bool DominatorTreeBase::dominates(Instruction *A, Instruction *B) {