1 files changed, 49 insertions, 0 deletions
diff --git a/include/llvm/Transforms/Utils/SSAUpdater.h b/include/llvm/Transforms/Utils/SSAUpdater.h
index e50a6b1..b4048b9 100644
--- a/include/llvm/Transforms/Utils/SSAUpdater.h
+++ b/include/llvm/Transforms/Utils/SSAUpdater.h
@@ -108,6 +108,55 @@ private:
   void operator=(const SSAUpdater&); // DO NOT IMPLEMENT
   SSAUpdater(const SSAUpdater&);     // DO NOT IMPLEMENT
 };
+  
+/// LoadAndStorePromoter - This little helper class provides a convenient way to
+/// promote a collection of loads and stores into SSA Form using the SSAUpdater.
+/// This handles complexities that SSAUpdater doesn't, such as multiple loads
+/// and stores in one block.
+///
+/// Clients of this class are expected to subclass this and implement the
+/// virtual methods.
+///
+class LoadAndStorePromoter {
+protected:
+  SSAUpdater &SSA;
+public:
+  LoadAndStorePromoter(const SmallVectorImpl<Instruction*> &Insts,
+                       SSAUpdater &S, StringRef Name = StringRef());
+  virtual ~LoadAndStorePromoter() {}
+  
+  /// run - This does the promotion.  Insts is a list of loads and stores to
+  /// promote, and Name is the basename for the PHIs to insert.  After this is
+  /// complete, the loads and stores are removed from the code.
+  void run(const SmallVectorImpl<Instruction*> &Insts) const;
+  
+  
+  /// Return true if the specified instruction is in the Inst list (which was
+  /// passed into the run method).  Clients should implement this with a more
+  /// efficient version if possible.
+  virtual bool isInstInList(Instruction *I,
+                            const SmallVectorImpl<Instruction*> &Insts) const {
+    for (unsigned i = 0, e = Insts.size(); i != e; ++i)
+      if (Insts[i] == I)
+        return true;
+    return false;
+  }
+  
+  /// doExtraRewritesBeforeFinalDeletion - This hook is invoked after all the
+  /// stores are found and inserted as available values, but 
+  virtual void doExtraRewritesBeforeFinalDeletion() const {
+  }
+  
+  /// replaceLoadWithValue - Clients can choose to implement this to get
+  /// notified right before a load is RAUW'd another value.
+  virtual void replaceLoadWithValue(LoadInst *LI, Value *V) const {
+  }
+
+  /// This is called before each instruction is deleted.
+  virtual void instructionDeleted(Instruction *I) const {
+  }
+
+};
 
 } // End llvm namespace