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/Target/X86/X86PadShortFunction.cpp b/llvm/lib/Target/X86/X86PadShortFunction.cpp
index f2ee437..1da0fad 100644
--- a/llvm/lib/Target/X86/X86PadShortFunction.cpp
+++ b/llvm/lib/Target/X86/X86PadShortFunction.cpp
@@ -96,10 +96,10 @@
 /// runOnMachineFunction - Loop over all of the basic blocks, inserting
 /// NOOP instructions before early exits.
 bool PadShortFunc::runOnMachineFunction(MachineFunction &MF) {
-  if (skipFunction(*MF.getFunction()))
+  if (skipFunction(MF.getFunction()))
     return false;
 
-  if (MF.getFunction()->optForSize()) {
+  if (MF.getFunction().optForSize()) {
     return false;
   }