[compiler-rt] TSAN: Report when thread is not live and referenced in pthread (PR #156921)

[via llvm-commits]

================
@@ -0,0 +1,18 @@
+// RUN: %clang_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
+
+#include <pthread.h>
+#include <stdio.h>
+
+void *fn(void *) { return NULL; }
+
+int main() {
+  pthread_t th;
+  int rc = pthread_create(&th, 0, fn, 0);
----------------
ghostway0 wrote:

what's UB here?

https://github.com/llvm/llvm-project/pull/156921