Blunder keep clearFlag(Token::NeedsCleaning)

at the beginning of ExpandBuiltinMacro to account for early returns
(e.g..in __DATE__ or __TIME__ expansion).

Author: mariusdr

clang/lib/Lex/PPMacroExpansion.cpp

@@ -1646,6 +1646,7 @@ void Preprocessor::ExpandBuiltinMacro(Token &Tok) {
 
   // Set up the return result.
   Tok.setIdentifierInfo(nullptr);
+  Tok.clearFlag(Token::NeedsCleaning);
   bool IsAtStartOfLine = Tok.isAtStartOfLine();
   bool HasLeadingSpace = Tok.hasLeadingSpace();
 

clang/test/Preprocessor/pr133574.c

@@ -0,0 +1,121 @@
+// RUN: %clang_cc1 -E -verify %s
+// expected-no-diagnostics
+
+#define DATE_LBR __D\
+ATE__
+
+const char* test1(void) {
+    return __DATE\
+__;
+}
+const char* test2(void) {
+    return DATE_LBR;
+}
+
+#define TIME_LBR __TIME_\
+_
+
+const char* test3(void) {
+    return __TIM\
+E__;
+}
+
+const char* test4(void) {
+    return TIME_LBR;
+}
+
+#define LINE_LBR __LI\
+NE__
+
+int test5(void) {
+    return _\
+_LINE__;
+}
+
+int test6(void) {
+    return LINE_LBR;
+}
+
+#define FILE_LBR __FI\
+LE__
+
+const char* test7(void) {
+    return __\
+FILE__;
+}
+
+const char* test8(void) {
+    return FILE_LBR;
+}
+
+#define FILE_NAME_LBR __FILE_NA\
+ME__
+
+const char* test9(void) {
+    return __FILE_NAM\
+E__;
+}
+
+const char* test10(void) {
+    return FILE_NAME_LBR;
+}
+
+#define BASE_FILE_LBR __BASE_FIL\
+E__
+
+const char* test11(void) {
+    return __BASE_\
+FILE__;
+}
+
+const char* test12(void) {
+    return BASE_FILE_LBR;
+}
+
+#define INCLUDE_LEVEL_LBR __INCLUDE\
+_LEVEL__
+
+int test13(void) {
+    return __IN\
+CLUDE_LEVEL__;
+}
+
+int test14(void) {
+    return INCLUDE_LEVEL_LBR;
+}
+
+#define TIMESTAMP_LBR __TIMESTA\
+MP__
+
+const char* test15(void) {
+    return __TIMESTA\
+MP__;
+}
+
+const char* test16(void) {
+    return TIMESTAMP_LBR;
+}
+
+#define FLT_EVAL_METHOD_LBR __FLT_EVAL_METH\
+OD__
+
+int test17(void) {
+    return __FL\
+T_EVAL_METHOD__;
+}
+
+int test18(void) {
+    return FLT_EVAL_METHOD_LBR;
+}
+
+#define COUNTER_LBR __COUNTE\
+R__
+
+int test19(void) {
+    return _\
+_COUNTER__;
+}
+
+int test20(void) {
+    return COUNTER_LBR;
+}