commit 5ed12dc1583e4abd91410a53c4a49b7ab194a3f2
Author: Samuel Thibault <samuel.thibault@ens-lyon.org>
Date:   Wed Aug 11 23:43:48 2021 +0200

    assert_*_backtrace: Tell the compiler that failures are unlikely

diff --git a/libshouldbeinlibc/assert-backtrace.h b/libshouldbeinlibc/assert-backtrace.h
index f49a537e..c1e51594 100644
--- a/libshouldbeinlibc/assert-backtrace.h
+++ b/libshouldbeinlibc/assert-backtrace.h
@@ -45,16 +45,16 @@ void __assert_perror_fail_backtrace (int errnum,
   __attribute__ ((noreturn, unused));
 
 #define assert_backtrace(expr)						\
-  ((expr)								\
+  (__builtin_expect(!!(expr), 1)					\
    ? (void) 0								\
    : __assert_fail_backtrace (__STRING(expr),				\
 			      __FILE__, __LINE__,			\
 			      __PRETTY_FUNCTION__))
 
 #define assert_perror_backtrace(expr)					\
-  ((expr == 0)								\
+  (__builtin_expect(((expr) == 0), 1)					\
    ? (void) 0								\
-   : __assert_perror_fail_backtrace (expr,				\
+   : __assert_perror_fail_backtrace ((expr),				\
 				     __FILE__, __LINE__,		\
 				     __PRETTY_FUNCTION__))
 
