[OPENMP50]Add parsing/sema analysis for nontemporal clause.

Add basic support for parsing/sema analysis of the nontemporal clause in
simd-based directives.
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index a2e4e7b..9258a6fb 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -11698,6 +11698,9 @@
   case OMPC_allocate:
     C = OMPAllocateClause::CreateEmpty(Context, Record.readInt());
     break;
+  case OMPC_nontemporal:
+    C = OMPNontemporalClause::CreateEmpty(Context, Record.readInt());
+    break;
   }
   assert(C && "Unknown OMPClause type");
 
@@ -12454,3 +12457,13 @@
   }
   C->setComponents(Components, ListSizes);
 }
+
+void OMPClauseReader::VisitOMPNontemporalClause(OMPNontemporalClause *C) {
+  C->setLParenLoc(Record.readSourceLocation());
+  unsigned NumVars = C->varlist_size();
+  SmallVector<Expr *, 16> Vars;
+  Vars.reserve(NumVars);
+  for (unsigned i = 0; i != NumVars; ++i)
+    Vars.push_back(Record.readSubExpr());
+  C->setVarRefs(Vars);
+}