[C++] Use 'nullptr'.

llvm-svn: 207394
diff --git a/llvm/lib/ExecutionEngine/JIT/JITMemoryManager.cpp b/llvm/lib/ExecutionEngine/JIT/JITMemoryManager.cpp
index d0e3813..584b93f 100644
--- a/llvm/lib/ExecutionEngine/JIT/JITMemoryManager.cpp
+++ b/llvm/lib/ExecutionEngine/JIT/JITMemoryManager.cpp
@@ -643,7 +643,7 @@
 }
 
 void DefaultJITMemoryManager::AllocateGOT() {
-  assert(GOTBase == 0 && "Cannot allocate the got multiple times");
+  assert(!GOTBase && "Cannot allocate the got multiple times");
   GOTBase = new uint8_t[sizeof(void*) * 8192];
   HasGOT = true;
 }