1 files changed, 115 insertions, 0 deletions
diff --git a/contrib/llvm/lib/CodeGen/BranchFolding.h b/contrib/llvm/lib/CodeGen/BranchFolding.h
new file mode 100644
index 000000000000..b08739564060
--- /dev/null
+++ b/contrib/llvm/lib/CodeGen/BranchFolding.h
@@ -0,0 +1,115 @@
+//===-- BranchFolding.h - Fold machine code branch instructions --*- C++ -*===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CODEGEN_BRANCHFOLDING_HPP
+#define LLVM_CODEGEN_BRANCHFOLDING_HPP
+
+#include "llvm/CodeGen/MachineBasicBlock.h"
+#include <vector>
+
+namespace llvm {
+  class MachineFunction;
+  class MachineModuleInfo;
+  class RegScavenger;
+  class TargetInstrInfo;
+  class TargetRegisterInfo;
+  template<typename T> class SmallVectorImpl;
+
+  class BranchFolder {
+  public:
+    explicit BranchFolder(bool defaultEnableTailMerge);
+
+    bool OptimizeFunction(MachineFunction &MF,
+                          const TargetInstrInfo *tii,
+                          const TargetRegisterInfo *tri,
+                          MachineModuleInfo *mmi);
+  private:
+    class MergePotentialsElt {
+      unsigned Hash;
+      MachineBasicBlock *Block;
+    public:
+      MergePotentialsElt(unsigned h, MachineBasicBlock *b)
+        : Hash(h), Block(b) {}
+
+      unsigned getHash() const { return Hash; }
+      MachineBasicBlock *getBlock() const { return Block; }
+
+      void setBlock(MachineBasicBlock *MBB) {
+        Block = MBB;
+      }
+
+      bool operator<(const MergePotentialsElt &) const;
+    };
+    typedef std::vector<MergePotentialsElt>::iterator MPIterator;
+    std::vector<MergePotentialsElt> MergePotentials;
+
+    class SameTailElt {
+      MPIterator MPIter;
+      MachineBasicBlock::iterator TailStartPos;
+    public:
+      SameTailElt(MPIterator mp, MachineBasicBlock::iterator tsp)
+        : MPIter(mp), TailStartPos(tsp) {}
+
+      MPIterator getMPIter() const {
+        return MPIter;
+      }
+      MergePotentialsElt &getMergePotentialsElt() const {
+        return *getMPIter();
+      }
+      MachineBasicBlock::iterator getTailStartPos() const {
+        return TailStartPos;
+      }
+      unsigned getHash() const {
+        return getMergePotentialsElt().getHash();
+      }
+      MachineBasicBlock *getBlock() const {
+        return getMergePotentialsElt().getBlock();
+      }
+      bool tailIsWholeBlock() const {
+        return TailStartPos == getBlock()->begin();
+      }
+
+      void setBlock(MachineBasicBlock *MBB) {
+        getMergePotentialsElt().setBlock(MBB);
+      }
+      void setTailStartPos(MachineBasicBlock::iterator Pos) {
+        TailStartPos = Pos;
+      }
+    };
+    std::vector<SameTailElt> SameTails;
+
+    bool EnableTailMerge;
+    const TargetInstrInfo *TII;
+    const TargetRegisterInfo *TRI;
+    MachineModuleInfo *MMI;
+    RegScavenger *RS;
+
+    bool TailMergeBlocks(MachineFunction &MF);
+    bool TryTailMergeBlocks(MachineBasicBlock* SuccBB,
+                       MachineBasicBlock* PredBB);
+    void ReplaceTailWithBranchTo(MachineBasicBlock::iterator OldInst,
+                                 MachineBasicBlock *NewDest);
+    MachineBasicBlock *SplitMBBAt(MachineBasicBlock &CurMBB,
+                                  MachineBasicBlock::iterator BBI1);
+    unsigned ComputeSameTails(unsigned CurHash, unsigned minCommonTailLength,
+                              MachineBasicBlock *SuccBB,
+                              MachineBasicBlock *PredBB);
+    void RemoveBlocksWithHash(unsigned CurHash, MachineBasicBlock* SuccBB,
+                                                MachineBasicBlock* PredBB);
+    unsigned CreateCommonTailOnlyBlock(MachineBasicBlock *&PredBB,
+                                       unsigned maxCommonTailLength);
+
+    bool OptimizeBranches(MachineFunction &MF);
+    bool OptimizeBlock(MachineBasicBlock *MBB);
+    void RemoveDeadBlock(MachineBasicBlock *MBB);
+    bool OptimizeImpDefsBlock(MachineBasicBlock *MBB);
+  };
+}
+
+#endif /* LLVM_CODEGEN_BRANCHFOLDING_HPP */