1 files changed, 20 insertions, 8 deletions

diff --git a/include/llvm/Analysis/ScalarEvolution.h b/include/llvm/Analysis/ScalarEvolution.h
index 3d37651525..4915bc6af2 100644
--- a/include/llvm/Analysis/ScalarEvolution.h
+++ b/include/llvm/Analysis/ScalarEvolution.h
@@ -426,14 +426,6 @@ namespace llvm {
     /// resolution.
     void ForgetSymbolicName(Instruction *I, const SCEV *SymName);
 
-    /// getBECount - Subtract the end and start values and divide by the step,
-    /// rounding up, to get the number of times the backedge is executed. Return
-    /// CouldNotCompute if an intermediate computation overflows.
-    const SCEV *getBECount(const SCEV *Start,
-                           const SCEV *End,
-                           const SCEV *Step,
-                           bool NoWrap);
-
     /// getBackedgeTakenInfo - Return the BackedgeTakenInfo for the given
     /// loop, lazily computing new values if the loop hasn't been analyzed
     /// yet.
@@ -498,6 +490,8 @@ namespace llvm {
     /// less-than is signed.
     ExitLimit HowManyLessThans(const SCEV *LHS, const SCEV *RHS,
                                const Loop *L, bool isSigned, bool IsSubExpr);
+    ExitLimit HowManyGreaterThans(const SCEV *LHS, const SCEV *RHS,
+                                  const Loop *L, bool isSigned, bool IsSubExpr);
 
     /// getPredecessorWithUniqueSuccessorForBB - Return a predecessor of BB
     /// (which may not be an immediate predecessor) which has exactly one
@@ -880,6 +874,24 @@ namespace llvm {
     virtual void verifyAnalysis() const;
 
   private:
+    /// Compute the backedge taken count knowing the interval difference, the
+    /// stride and presence of the equality in the comparison.
+    const SCEV *computeBECount(const SCEV *Delta, const SCEV *Stride,
+                               bool Equality);
+
+    /// Verify if an linear IV with positive stride can overflow when in a 
+    /// less-than comparison, knowing the invariant term of the comparison,
+    /// the stride and the knowledge of NSW/NUW flags on the recurrence.
+    bool doesIVOverflowOnLT(const SCEV *RHS, const SCEV *Stride,
+                            bool IsSigned, bool NoWrap);
+
+    /// Verify if an linear IV with negative stride can overflow when in a 
+    /// greater-than comparison, knowing the invariant term of the comparison,
+    /// the stride and the knowledge of NSW/NUW flags on the recurrence.
+    bool doesIVOverflowOnGT(const SCEV *RHS, const SCEV *Stride,
+                            bool IsSigned, bool NoWrap);
+
+  private:
     FoldingSet<SCEV> UniqueSCEVs;
     BumpPtrAllocator SCEVAllocator;