Index: clang/lib/Format/UnwrappedLineParser.cpp
===================================================================
--- clang/lib/Format/UnwrappedLineParser.cpp
+++ clang/lib/Format/UnwrappedLineParser.cpp
@@ -2605,8 +2605,7 @@
   FormatToken *Tok = nullptr;
 
   if (Style.InsertBraces && !Line->InPPDirective && !Line->Tokens.empty() &&
-      PreprocessorDirectives.empty()) {
-    assert(!Line->Tokens.empty());
+      PreprocessorDirectives.empty() && FormatTok->isNot(tok::semi)) {
     Tok = Style.BraceWrapping.AfterControlStatement == FormatStyle::BWACS_Never
               ? getLastNonComment(*Line)
               : Line->Tokens.back().Tok;
Index: clang/unittests/Format/FormatTest.cpp
===================================================================
--- clang/unittests/Format/FormatTest.cpp
+++ clang/unittests/Format/FormatTest.cpp
@@ -25327,6 +25327,30 @@
                "}",
                Style);
 
+  verifyFormat("do {\n"
+               "#if 0\n"
+               " if (a) {\n"
+               "#else\n"
+               "  if (b) {\n"
+               "#endif\n"
+               "}\n"
+               "}\n"
+               "while (0)\n"
+               "  ;",
+               Style);
+  // TODO: Replace the test above with the one below after #57539 is fixed.
+#if 0
+  verifyFormat("do {\n"
+               "#if 0\n"
+               "  if (a) {\n"
+               "#else\n"
+               "  if (b) {\n"
+               "#endif\n"
+               "  }\n"
+               "} while (0);",
+               Style);
+#endif
+
   Style.ColumnLimit = 15;
 
   verifyFormat("#define A     \\\n"