[PATCH v3 16/18] tftp: add debug_assert() macro

[Enrico Scholz]

Is a noop in normal cases (when compiler sees that condition can be
evaluated without sideeffects) but allows optimizations based on the
condition.

E.g. in

| void foo(int a)
| {
|     debug_assert(a == 23);
|
|     if (a == 23)
|         return;
|
|     bar();
| }

the call to 'bar()' will be optimized away.

Signed-off-by: Enrico Scholz <enrico.scholz at sigma-chemnitz.de>
---
 fs/tftp.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/fs/tftp.c b/fs/tftp.c
index c96c8917633a..d02ca750cd6d 100644
--- a/fs/tftp.c
+++ b/fs/tftp.c
@@ -75,6 +75,15 @@
 
 #define TFTP_ERR_RESEND	1
 
+#ifdef DEBUG
+#  define debug_assert(_cond)	BUG_ON(!(_cond))
+#else
+#  define debug_assert(_cond) do {			\
+		if (!(_cond))				\
+			__builtin_unreachable();	\
+	} while (0)
+#endif
+
 static int g_tftp_window_size = DIV_ROUND_UP(TFTP_MAX_WINDOW_SIZE, 2);
 
 struct file_priv {
-- 
2.37.1