Revert 131172 as it is causing clang to miscompile itself. I will try
to provide a reduced testcase.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131176 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/BranchFolding.h b/lib/CodeGen/BranchFolding.h
index 4daf4ec..15dfa7f 100644
--- a/lib/CodeGen/BranchFolding.h
+++ b/lib/CodeGen/BranchFolding.h
@@ -19,10 +19,11 @@
   class RegScavenger;
   class TargetInstrInfo;
   class TargetRegisterInfo;
+  template<typename T> class SmallVectorImpl;
 
   class BranchFolder {
   public:
-    explicit BranchFolder(bool defaultEnableTailMerge, bool CommonHoist);
+    explicit BranchFolder(bool defaultEnableTailMerge);
 
     bool OptimizeFunction(MachineFunction &MF,
                           const TargetInstrInfo *tii,
@@ -84,7 +85,6 @@
     std::vector<SameTailElt> SameTails;
 
     bool EnableTailMerge;
-    bool EnableHoistCommonCode;
     const TargetInstrInfo *TII;
     const TargetRegisterInfo *TRI;
     MachineModuleInfo *MMI;
@@ -110,9 +110,6 @@
     bool OptimizeBlock(MachineBasicBlock *MBB);
     void RemoveDeadBlock(MachineBasicBlock *MBB);
     bool OptimizeImpDefsBlock(MachineBasicBlock *MBB);
-
-    bool HoistCommonCode(MachineFunction &MF);
-    bool HoistCommonCodeInSuccs(MachineBasicBlock *MBB);
   };
 }