Use DominatorTree instead of ETForest.
This allows faster immediate domiantor walk.

llvm-svn: 37500
diff --git a/llvm/lib/Transforms/Scalar/LICM.cpp b/llvm/lib/Transforms/Scalar/LICM.cpp
index 8139959..2662a60 100644
--- a/llvm/lib/Transforms/Scalar/LICM.cpp
+++ b/llvm/lib/Transforms/Scalar/LICM.cpp
@@ -565,7 +565,7 @@
     if (AI) {
       std::vector<AllocaInst*> Allocas;
       Allocas.push_back(AI);
-      PromoteMemToReg(Allocas, *ET, *DF, CurAST);
+      PromoteMemToReg(Allocas, *DT, *DF, CurAST);
     }
   }
 }
@@ -746,7 +746,7 @@
   PromotedAllocas.reserve(PromotedValues.size());
   for (unsigned i = 0, e = PromotedValues.size(); i != e; ++i)
     PromotedAllocas.push_back(PromotedValues[i].first);
-  PromoteMemToReg(PromotedAllocas, *ET, *DF, CurAST);
+  PromoteMemToReg(PromotedAllocas, *DT, *DF, CurAST);
 }
 
 /// FindPromotableValuesInLoop - Check the current loop for stores to definite