diff --git a/lib/CodeGen/MachineBasicBlock.cpp b/lib/CodeGen/MachineBasicBlock.cpp
index 1d68d7c..51f0f9d 100644
--- a/lib/CodeGen/MachineBasicBlock.cpp
+++ b/lib/CodeGen/MachineBasicBlock.cpp
@@ -248,13 +248,13 @@
     fromMBB->removeSuccessor(fromMBB->succ_begin());
 }
 
-bool MachineBasicBlock::isSuccessor(MachineBasicBlock *MBB) const {
+bool MachineBasicBlock::isSuccessor(const MachineBasicBlock *MBB) const {
   std::vector<MachineBasicBlock *>::const_iterator I =
     std::find(Successors.begin(), Successors.end(), MBB);
   return I != Successors.end();
 }
 
-bool MachineBasicBlock::isLayoutSuccessor(MachineBasicBlock *MBB) const {
+bool MachineBasicBlock::isLayoutSuccessor(const MachineBasicBlock *MBB) const {
   MachineFunction::const_iterator I(this);
   return next(I) == MachineFunction::const_iterator(MBB);
 }