Cherry-pick upstream r238083

lib/Sema/SemaChecking.cpp

 //===--- SemaChecking.cpp - Extra Semantic Checking -----------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 //  This file implements extra semantic analysis beyond what is enforced
@@ skipping 6034 matching lines @@
                                          Expr *Constant, Expr *Other,
                                          llvm::APSInt Value,
                                          bool RhsConstant) {
   // Disable warning in template instantiations.
   if (!S.ActiveTemplateInstantiations.empty())
     return;
 
   // TODO: Investigate using GetExprRange() to get tighter bounds
   // on the bit ranges.
   QualType OtherT = Other->getType();
-  if (const AtomicType *AT = dyn_cast<AtomicType>(OtherT))
+  if (const auto *AT = OtherT->getAs<AtomicType>())
     OtherT = AT->getValueType();
   IntRange OtherRange = IntRange::forValueOfType(S.Context, OtherT);
   unsigned OtherWidth = OtherRange.Width;
 
   bool OtherIsBooleanType = Other->isKnownToHaveBooleanValue();
 
   // 0 values are handled later by CheckTrivialUnsignedComparison().
   if ((Value == 0) && (!OtherIsBooleanType))
     return;
 
@@ skipping 3252 matching lines @@
       mismatch = !isLayoutCompatible(Context, ArgumentType, RequiredType);
 
   if (mismatch)
     Diag(ArgumentExpr->getExprLoc(), diag::warn_type_safety_type_mismatch)
         << ArgumentType << ArgumentKind
         << TypeInfo.LayoutCompatible << RequiredType
         << ArgumentExpr->getSourceRange()
         << TypeTagExpr->getSourceRange();
 }