Index: lib/AST/StmtPrinter.cpp
===================================================================
--- lib/AST/StmtPrinter.cpp
+++ lib/AST/StmtPrinter.cpp
@@ -1230,8 +1230,8 @@
   default:
     if (value < 256 && isPrintable((unsigned char)value))
       OS << "'" << (char)value << "'";
-    else if (value < 256)
-      OS << "'\\x" << llvm::format("%02x", value) << "'";
+    else if (value < 256 || CharacterLiteral::Ascii == Node->getKind())
+      OS << "'\\x" << llvm::format("%02x", (unsigned char)value) << "'";
     else if (value <= 0xFFFF)
       OS << "'\\u" << llvm::format("%04x", value) << "'";
     else
Index: test/Sema/ast-print.c
===================================================================
--- test/Sema/ast-print.c
+++ test/Sema/ast-print.c
@@ -66,3 +66,6 @@
     c;
   });
 }
+
+// CHECK: char c = '\x80';
+char c = '\200';