[C++11] More 'nullptr' conversion. In some cases just using a boolean check instead of comparing to nullptr.

llvm-svn: 206252
diff --git a/llvm/lib/Support/FoldingSet.cpp b/llvm/lib/Support/FoldingSet.cpp
index d857559..4635114 100644
--- a/llvm/lib/Support/FoldingSet.cpp
+++ b/llvm/lib/Support/FoldingSet.cpp
@@ -305,7 +305,7 @@
 /// is not already in the map.  InsertPos must be obtained from 
 /// FindNodeOrInsertPos.
 void FoldingSetImpl::InsertNode(Node *N, void *InsertPos) {
-  assert(N->getNextInBucket() == 0);
+  assert(!N->getNextInBucket());
   // Do we need to grow the hashtable?
   if (NumNodes+1 > NumBuckets*2) {
     GrowHashTable();