https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120449
--- Comment #6 from Zartaj Majeed <zmajeed at sbcglobal dot net> ---
Thanks - the following works
diff --git a/gcc/c-family/c-common.cc b/gcc/c-family/c-common.cc
index f71cb2652d5..6d7ef006c6a 100644
--- a/gcc/c-family/c-common.cc
+++ b/gcc/c-family/c-common.cc
@@ -3318,7 +3318,7 @@ shorten_compare (location_t loc, tree *op0_ptr, tree
*op1_ptr,
warning. */
tree folded_op0 = fold_for_warn (op0);
bool warn =
- warn_type_limits && !in_system_header_at (loc)
+ warn_type_limits && diagnostic_report_warnings_p(global_dc, loc)
&& !(TREE_CODE (folded_op0) == INTEGER_CST
&& !TREE_OVERFLOW (convert (c_common_signed_type (type),
----------------
g++ -c -Wtype-limits -std=c++20 -Wsystem-headers typelimits.cpp
In file included from requires_hosted.h:31,
from semaphore:36,
from typelimits.cpp:1:
semaphore_base.h: In constructor
‘std::__atomic_semaphore::__atomic_semaphore(std::__detail::__platform_wait_t)’:
semaphore_base.h:178:7: warning: comparison of unsigned expression in ‘>= 0’ is
always true [-Wtype-limits]
178 | __glibcxx_assert(__count >= 0 && __count <= _S_max);
| ^~~~~~~~~~~~~~~~
Though position of underline is off
----------------
Underline is wrong and confusing with --save-temps
g++ -c -Wtype-limits -std=c++20 -Wsystem-headers --save-temps typelimits.cpp
In file included from semaphore:39,
from typelimits.cpp:1:
semaphore_base.h: In constructor
‘std::__atomic_semaphore::__atomic_semaphore(std::__detail::__platform_wait_t)’:
semaphore_base.h:178:47: warning: comparison of unsigned expression in ‘>= 0’
is always true [-Wtype-limits]
178 | __glibcxx_assert(__count >= 0 && __count <= _S_max);
| ~~~~~~~~^~~~
----------------
Underline is correctly positioned with -P
g++ -c -Wtype-limits -std=c++20 -Wsystem-headers --save-temps -P typelimits.cpp
typelimits.ii: In constructor
‘std::__atomic_semaphore::__atomic_semaphore(std::__detail::__platform_wait_t)’:
typelimits.ii:10140:47: warning: comparison of unsigned expression in ‘>= 0’ is
always true [-Wtype-limits]
10140 | do { if (__builtin_expect(!bool(__count >= 0 && __count <=
_S_max), false)) std::__glibcxx_assert_fail("semaphore_base.h", 178,
__PRETTY_FUNCTION__, "__count >= 0 && __count <= _S_max"); } while (false);
| ~~~~~~~~^~~~
