Add an additional check for null pointer before accessing PatternDecl.

llvm-svn: 132175
diff --git a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
index 3c0d34b..e9c09c3 100644
--- a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -2341,7 +2341,7 @@
     Pattern = PatternDecl->getBody(PatternDecl);
   }
 
-  if (!Pattern && !PatternDecl->isDefaulted()) {
+  if (!Pattern && PatternDecl && !PatternDecl->isDefaulted()) {
     if (DefinitionRequired) {
       if (Function->getPrimaryTemplate())
         Diag(PointOfInstantiation,