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

llvm-svn: 205831
diff --git a/llvm/lib/IR/LLVMContext.cpp b/llvm/lib/IR/LLVMContext.cpp
index 0c92200..bd87ef3 100644
--- a/llvm/lib/IR/LLVMContext.cpp
+++ b/llvm/lib/IR/LLVMContext.cpp
@@ -126,7 +126,7 @@
 
 void LLVMContext::diagnose(const DiagnosticInfo &DI) {
   // If there is a report handler, use it.
-  if (pImpl->DiagnosticHandler != 0) {
+  if (pImpl->DiagnosticHandler) {
     pImpl->DiagnosticHandler(DI, pImpl->DiagnosticContext);
     return;
   }