diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 0f37bcf0d5c85..d8632f53bb1ee 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -3463,8 +3463,7 @@ static APSInt extractStringLiteralCharacter(EvalInfo &Info, const Expr *Lit,
   assert(CAT && "string literal isn't an array");
   QualType CharType = CAT->getElementType();
   assert(CharType->isIntegerType() && "unexpected character type");
-
-  APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(),
+  APSInt Value(Info.Ctx.getTypeSize(CharType),
                CharType->isUnsignedIntegerType());
   if (Index < S->getLength())
     Value = S->getCodeUnit(Index);
@@ -3487,7 +3486,7 @@ static void expandStringLiteral(EvalInfo &Info, const StringLiteral *S,
   unsigned Elts = CAT->getSize().getZExtValue();
   Result = APValue(APValue::UninitArray(),
                    std::min(S->getLength(), Elts), Elts);
-  APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(),
+  APSInt Value(Info.Ctx.getTypeSize(CharType),
                CharType->isUnsignedIntegerType());
   if (Result.hasArrayFiller())
     Result.getArrayFiller() = APValue(Value);