[libc-commits] [libc] [libc] Added support for fixed-points in ``is_signed`` and ``is_unsigned``. (PR #133371)

[via libc-commits]

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@@ -8,20 +8,98 @@
 #ifndef LLVM_LIBC_SRC___SUPPORT_CPP_TYPE_TRAITS_IS_SIGNED_H
 #define LLVM_LIBC_SRC___SUPPORT_CPP_TYPE_TRAITS_IS_SIGNED_H
 
+#include "include/llvm-libc-macros/stdfix-macros.h"
 #include "src/__support/CPP/type_traits/bool_constant.h"
 #include "src/__support/CPP/type_traits/is_arithmetic.h"
+#include "src/__support/CPP/type_traits/is_fixed_point.h"
 #include "src/__support/macros/attributes.h"
 #include "src/__support/macros/config.h"
 
 namespace LIBC_NAMESPACE_DECL {
 namespace cpp {
 
-// is_signed
+// Primary template: handles arithmetic and signed fixed-point types
 template <typename T>
 struct is_signed : bool_constant<(is_arithmetic_v<T> && (T(-1) < T(0)))> {
   LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
   LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
 };
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lntue wrote:

So I just tested locally, and the following seems to work without all the specializations:
```
struct is_signed : bool_constant<
    (is_fixed_point_v<T> && T(-0.5) < T(0)) ||
    (is_arithmetic_v<T> && (T(-1) < T(0)))> {
    ...
};
```

https://github.com/llvm/llvm-project/pull/133371