[MachineOutliner][NFC] Exit getOutliningType if there are < 2 candidates

Since we never outline anything with fewer than 2 occurrences, there's no
reason to compute cost model information if there's less than that.

llvm-svn: 346803
diff --git a/llvm/lib/CodeGen/MachineOutliner.cpp b/llvm/lib/CodeGen/MachineOutliner.cpp
index 1a3a2cf..6b9fadd 100644
--- a/llvm/lib/CodeGen/MachineOutliner.cpp
+++ b/llvm/lib/CodeGen/MachineOutliner.cpp
@@ -1127,8 +1127,9 @@
     OutlinedFunction OF =
         TII->getOutliningCandidateInfo(CandidatesForRepeatedSeq);
 
-    // If we deleted every candidate, then there's nothing to outline.
-    if (OF.Candidates.empty())
+    // If we deleted too many candidates, then there's nothing worth outlining.
+    // FIXME: This should take target-specified instruction sizes into account.
+    if (OF.Candidates.size() < 2)
       continue;
 
     std::vector<unsigned> Seq;