Allow removeLiveIn to be called with a register that isn't live-in.

This avoids the silly double search:

  if (isLiveIn(Reg))
    removeLiveIn(Reg);

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153592 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineBasicBlock.cpp b/lib/CodeGen/MachineBasicBlock.cpp
index ca8a8e8..6c8a107 100644
--- a/lib/CodeGen/MachineBasicBlock.cpp
+++ b/lib/CodeGen/MachineBasicBlock.cpp
@@ -321,8 +321,8 @@
 void MachineBasicBlock::removeLiveIn(unsigned Reg) {
   std::vector<unsigned>::iterator I =
     std::find(LiveIns.begin(), LiveIns.end(), Reg);
-  assert(I != LiveIns.end() && "Not a live in!");
-  LiveIns.erase(I);
+  if (I != LiveIns.end())
+    LiveIns.erase(I);
 }
 
 bool MachineBasicBlock::isLiveIn(unsigned Reg) const {