X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=blobdiff_plain;f=include%2Fllvm%2FAnalysis%2FScalarEvolutionExpander.h;h=e5647860db5c136f5d043f36f7c60931937399a4;hp=8ec2078258d111be7a78ee6bbfe48f13cbd7fd24;hb=72644dfdcd64c186ae04e7a4a125429603e3e7cd;hpb=cd52a7a381a73c53ec4ef517ad87f19808cb1a28

diff --git a/include/llvm/Analysis/ScalarEvolutionExpander.h b/include/llvm/Analysis/ScalarEvolutionExpander.h
index 8ec2078258d..e5647860db5 100644
--- a/include/llvm/Analysis/ScalarEvolutionExpander.h
+++ b/include/llvm/Analysis/ScalarEvolutionExpander.h
@@ -117,9 +117,13 @@ namespace llvm {
 
     /// \brief Return true for expressions that may incur non-trivial cost to
     /// evaluate at runtime.
-    bool isHighCostExpansion(const SCEV *Expr, Loop *L) {
+    /// 'At' is an optional parameter which specifies point in code where user
+    /// is going to expand this expression. Sometimes this knowledge can lead to
+    /// a more accurate cost estimation.
+    bool isHighCostExpansion(const SCEV *Expr, Loop *L,
+                             const Instruction *At = nullptr) {
       SmallPtrSet<const SCEV *, 8> Processed;
-      return isHighCostExpansionHelper(Expr, L, Processed);
+      return isHighCostExpansionHelper(Expr, L, At, Processed);
     }
 
     /// \brief This method returns the canonical induction variable of the
@@ -193,11 +197,20 @@ namespace llvm {
 
     void setChainedPhi(PHINode *PN) { ChainedPhis.insert(PN); }
 
+    /// \brief Try to find LLVM IR value for 'S' available at the point 'At'.
+    // 'L' is a hint which tells in which loop to look for the suitable value.
+    // On success return value which is equivalent to the expanded 'S' at point
+    // 'At'. Return nullptr if value was not found.
+    // Note that this function does not perform exhaustive search. I.e if it
+    // didn't find any value it does not mean that there is no such value.
+    Value *findExistingExpansion(const SCEV *S, const Instruction *At, Loop *L);
+
   private:
     LLVMContext &getContext() const { return SE.getContext(); }
 
     /// \brief Recursive helper function for isHighCostExpansion.
     bool isHighCostExpansionHelper(const SCEV *S, Loop *L,
+                                   const Instruction *At,
                                    SmallPtrSetImpl<const SCEV *> &Processed);
 
     /// \brief Insert the specified binary operator, doing a small amount