[PATCH 1/2] cdefs: merge from glibc

[Paul Eggert]

* lib/cdefs.h (__glibc_safe_or_unknown_len):
Use glibc’s newer version.
---
 ChangeLog   |  6 ++++++
 lib/cdefs.h | 12 ++++++------
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 02be5e2317..f1a154027a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2022-05-05  Paul Eggert  <eggert@cs.ucla.edu>
+
+       cdefs: merge from glibc
+       * lib/cdefs.h (__glibc_safe_or_unknown_len):
+       Use glibc’s newer version.
+
 2022-05-02  Paul Eggert  <eggert@cs.ucla.edu>
 
        gettime-res: help the compiler
diff --git a/lib/cdefs.h b/lib/cdefs.h
index cb2514504f..7b8ed5b344 100644
--- a/lib/cdefs.h
+++ b/lib/cdefs.h
@@ -164,13 +164,13 @@
    || (__builtin_constant_p (__l) && (__l) > 0))
 
 /* Length is known to be safe at compile time if the __L * __S <= __OBJSZ
-   condition can be folded to a constant and if it is true.  The -1 check is
-   redundant because since it implies that __glibc_safe_len_cond is true.  */
+   condition can be folded to a constant and if it is true, or unknown (-1) */
 #define __glibc_safe_or_unknown_len(__l, __s, __osz) \
-  (__glibc_unsigned_or_positive (__l)                                        \
-   && __builtin_constant_p (__glibc_safe_len_cond ((__SIZE_TYPE__) (__l),     \
-                                                  __s, __osz))               \
-   && __glibc_safe_len_cond ((__SIZE_TYPE__) (__l), __s, __osz))
+  ((__osz) == (__SIZE_TYPE__) -1                                             \
+   || (__glibc_unsigned_or_positive (__l)                                    \
+       && __builtin_constant_p (__glibc_safe_len_cond ((__SIZE_TYPE__) (__l), \
+                                                      (__s), (__osz)))       \
+       && __glibc_safe_len_cond ((__SIZE_TYPE__) (__l), (__s), (__osz))))
 
 /* Conversely, we know at compile time that the length is unsafe if the
    __L * __S <= __OBJSZ condition can be folded to a constant and if it is
-- 
2.35.1