--- a/main/main.c
+++ b/main/main.c
@@ -2563,6 +2563,12 @@
 #endif

 	zend_observer_shutdown();
+
+	/* spc-pgo: explicit profile flush so embed/frankenphp callers that exit
+	 * via SYS_exit_group (skipping libc atexit) still get .profraw written.
+	 * Weak symbol → no-op in non-PGO builds. */
+	{ extern int __llvm_profile_write_file(void) __attribute__((weak));
+	  if (__llvm_profile_write_file) __llvm_profile_write_file(); }
 }
 /* }}} */