Index: clang-tools-extra/clangd/SourceCode.cpp
===================================================================
--- clang-tools-extra/clangd/SourceCode.cpp
+++ clang-tools-extra/clangd/SourceCode.cpp
@@ -59,7 +59,7 @@
   // Astral codepoints are encoded as 4 bytes in UTF-8, starting with 11110xxx.
   for (size_t I = 0; I < U8.size();) {
     unsigned char C = static_cast<unsigned char>(U8[I]);
-    if (LLVM_LIKELY(!(C & 0x80))) { // ASCII character.
+    if (LLVM_LIKELY(!(C & 0x100))) { // ASCII or extended ASCII character.
       if (CB(1, 1))
         return true;
       ++I;