MachineFunction: Return reference from getFunction(); NFC

The Function can never be nullptr so we can return a reference.

llvm-svn: 320884
diff --git a/llvm/lib/CodeGen/RegAllocPBQP.cpp b/llvm/lib/CodeGen/RegAllocPBQP.cpp
index 1a9ffb1..351e91c 100644
--- a/llvm/lib/CodeGen/RegAllocPBQP.cpp
+++ b/llvm/lib/CodeGen/RegAllocPBQP.cpp
@@ -799,7 +799,7 @@
   findVRegIntervalsToAlloc(MF, LIS);
 
 #ifndef NDEBUG
-  const Function &F = *MF.getFunction();
+  const Function &F = MF.getFunction();
   std::string FullyQualifiedName =
     F.getParent()->getModuleIdentifier() + "." + F.getName().str();
 #endif