Index: llvm/trunk/include/llvm/Analysis/LoopAccessAnalysis.h
===================================================================
--- llvm/trunk/include/llvm/Analysis/LoopAccessAnalysis.h
+++ llvm/trunk/include/llvm/Analysis/LoopAccessAnalysis.h
@@ -179,7 +179,12 @@
     /// \brief Dependence types that don't prevent vectorization.
     static bool isSafeForVectorization(DepType Type);
 
-    /// \brief Lexically backward dependence types.
+    /// \brief Lexically forward dependence.
+    bool isForward() const;
+    /// \brief Lexically backward dependence.
+    bool isBackward() const;
+
+    /// \brief May be a lexically backward dependence type (includes Unknown).
     bool isPossiblyBackward() const;
 
     /// \brief Print the dependence.  \p Instr is used to map the instruction
Index: llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp
===================================================================
--- llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp
+++ llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp
@@ -910,14 +910,14 @@
   llvm_unreachable("unexpected DepType!");
 }
 
-bool MemoryDepChecker::Dependence::isPossiblyBackward() const {
+bool MemoryDepChecker::Dependence::isBackward() const {
   switch (Type) {
   case NoDep:
   case Forward:
   case ForwardButPreventsForwarding:
+  case Unknown:
     return false;
 
-  case Unknown:
   case BackwardVectorizable:
   case Backward:
   case BackwardVectorizableButPreventsForwarding:
@@ -926,6 +926,26 @@
   llvm_unreachable("unexpected DepType!");
 }
 
+bool MemoryDepChecker::Dependence::isPossiblyBackward() const {
+  return isBackward() || Type == Unknown;
+}
+
+bool MemoryDepChecker::Dependence::isForward() const {
+  switch (Type) {
+  case Forward:
+  case ForwardButPreventsForwarding:
+    return true;
+
+  case NoDep:
+  case Unknown:
+  case BackwardVectorizable:
+  case Backward:
+  case BackwardVectorizableButPreventsForwarding:
+    return false;
+  }
+  llvm_unreachable("unexpected DepType!");
+}
+
 bool MemoryDepChecker::couldPreventStoreLoadForward(unsigned Distance,
                                                     unsigned TypeByteSize) {
   // If loads occur at a distance that is not a multiple of a feasible vector