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[libc] Added support for fixed-points in is_signed and is_unsigned. #133371

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Merged
lntue merged 9 commits into from
Apr 2, 2025
Merged

[libc] Added support for fixed-points in is_signed and is_unsigned. #133371

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d967f43
added support of fixed-points in is_signed and is_unsigned
Mar 28, 2025
b778f8f
minor changes
Mar 28, 2025
aac912f
removed redundant headers
Mar 28, 2025
dc3a4d5
minor changes
Mar 28, 2025
b835679
clang formatting
Mar 28, 2025
a81375a
clang formatter
Mar 28, 2025
ce28db0
added all fixed-points explicitly
Mar 28, 2025
5d0229b
added all fixed-points explicitly
Mar 28, 2025
b448b38
changed the design pattern
Mar 31, 2025
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59 changes: 57 additions & 2 deletions libc/src/__support/CPP/type_traits/is_signed.h
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Original file line number Diff line number Diff line change
Expand Up @@ -10,18 +10,73 @@

#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)))> {
struct is_signed : bool_constant<((is_fixed_point_v<T> || is_arithmetic_v<T>) &&
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@lntue lntue Mar 28, 2025

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probably you could change it to:

(is_fixed_point_v<T> && T(-0.5) < T(0)) || (is_arithmetic_v<T> && T(-1) < T(0))

and remove all the fixed point specializations.

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@kr-2003 kr-2003 Mar 28, 2025

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it won't work. even if the value is just less than 0, it will try to wrap around in unsigned type(and its not possible in fixed-points). I have tried it out.

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@lntue lntue Mar 29, 2025

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@PiJoules is there problem with constexpr for fixed point type in clang?

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@PiJoules PiJoules Mar 31, 2025

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What's the failure mode? Is it a compilation error or failure in one of the tests?

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@kr-2003 kr-2003 Mar 31, 2025

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What's the failure mode? Is it a compilation error or failure in one of the tests?

i have explained here #133680

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@PiJoules PiJoules Mar 31, 2025

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Replied to the issue.

tl;dr overflow for non-saturating types isn't defined, so unsigned _Fract(-1) can't be constant evaluated. If you want to check if a type is signed, I think you can do FXRep<T>::MIN() < FXRep::ZERO(). I also need to update the diagnostic since it's misleading.

(T(-1) < T(0)))> {
LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
};

#ifdef LIBC_COMPILER_HAS_FIXED_POINT
// Specializations for unsigned fixed-point types
template <> struct is_signed<unsigned short _Fract> : bool_constant<false> {
LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
};
template <> struct is_signed<unsigned _Fract> : bool_constant<false> {
LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
};
template <> struct is_signed<unsigned long _Fract> : bool_constant<false> {
LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
};
template <> struct is_signed<unsigned short _Accum> : bool_constant<false> {
LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
};
template <> struct is_signed<unsigned _Accum> : bool_constant<false> {
LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
};
template <> struct is_signed<unsigned long _Accum> : bool_constant<false> {
LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
};
template <> struct is_signed<unsigned short sat _Fract> : bool_constant<false> {
LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
};
template <> struct is_signed<unsigned sat _Fract> : bool_constant<false> {
LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
};
template <> struct is_signed<unsigned long sat _Fract> : bool_constant<false> {
LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
};
template <> struct is_signed<unsigned short sat _Accum> : bool_constant<false> {
LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
};
template <> struct is_signed<unsigned sat _Accum> : bool_constant<false> {
LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
};
template <> struct is_signed<unsigned long sat _Accum> : bool_constant<false> {
LIBC_INLINE constexpr operator bool() const { return is_signed::value; }
LIBC_INLINE constexpr bool operator()() const { return is_signed::value; }
};
#endif // LIBC_COMPILER_HAS_FIXED_POINT

template <typename T>
LIBC_INLINE_VAR constexpr bool is_signed_v = is_signed<T>::value;

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61 changes: 59 additions & 2 deletions libc/src/__support/CPP/type_traits/is_unsigned.h
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Original file line number Diff line number Diff line change
Expand Up @@ -10,18 +10,75 @@

#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_unsigned
// Primary template: handles arithmetic and signed fixed-point types
template <typename T>
struct is_unsigned : bool_constant<(is_arithmetic_v<T> && (T(-1) > T(0)))> {
struct is_unsigned
: bool_constant<((is_fixed_point_v<T> || is_arithmetic_v<T>) &&
(T(-1) > T(0)))> {
LIBC_INLINE constexpr operator bool() const { return is_unsigned::value; }
LIBC_INLINE constexpr bool operator()() const { return is_unsigned::value; }
};

#ifdef LIBC_COMPILER_HAS_FIXED_POINT
// Specializations for unsigned fixed-point types
template <> struct is_unsigned<unsigned short _Fract> : bool_constant<true> {
LIBC_INLINE constexpr operator bool() const { return is_unsigned::value; }
LIBC_INLINE constexpr bool operator()() const { return is_unsigned::value; }
};
template <> struct is_unsigned<unsigned _Fract> : bool_constant<true> {
LIBC_INLINE constexpr operator bool() const { return is_unsigned::value; }
LIBC_INLINE constexpr bool operator()() const { return is_unsigned::value; }
};
template <> struct is_unsigned<unsigned long _Fract> : bool_constant<true> {
LIBC_INLINE constexpr operator bool() const { return is_unsigned::value; }
LIBC_INLINE constexpr bool operator()() const { return is_unsigned::value; }
};
template <> struct is_unsigned<unsigned short accum> : bool_constant<true> {
LIBC_INLINE constexpr operator bool() const { return is_unsigned::value; }
LIBC_INLINE constexpr bool operator()() const { return is_unsigned::value; }
};
template <> struct is_unsigned<unsigned accum> : bool_constant<true> {
LIBC_INLINE constexpr operator bool() const { return is_unsigned::value; }
LIBC_INLINE constexpr bool operator()() const { return is_unsigned::value; }
};
template <> struct is_unsigned<unsigned long accum> : bool_constant<true> {
LIBC_INLINE constexpr operator bool() const { return is_unsigned::value; }
LIBC_INLINE constexpr bool operator()() const { return is_unsigned::value; }
};
template <>
struct is_unsigned<unsigned short sat _Fract> : bool_constant<true> {
LIBC_INLINE constexpr operator bool() const { return is_unsigned::value; }
LIBC_INLINE constexpr bool operator()() const { return is_unsigned::value; }
};
template <> struct is_unsigned<unsigned sat _Fract> : bool_constant<true> {
LIBC_INLINE constexpr operator bool() const { return is_unsigned::value; }
LIBC_INLINE constexpr bool operator()() const { return is_unsigned::value; }
};
template <> struct is_unsigned<unsigned long sat _Fract> : bool_constant<true> {
LIBC_INLINE constexpr operator bool() const { return is_unsigned::value; }
LIBC_INLINE constexpr bool operator()() const { return is_unsigned::value; }
};
template <> struct is_unsigned<unsigned short sat accum> : bool_constant<true> {
LIBC_INLINE constexpr operator bool() const { return is_unsigned::value; }
LIBC_INLINE constexpr bool operator()() const { return is_unsigned::value; }
};
template <> struct is_unsigned<unsigned sat accum> : bool_constant<true> {
LIBC_INLINE constexpr operator bool() const { return is_unsigned::value; }
LIBC_INLINE constexpr bool operator()() const { return is_unsigned::value; }
};
template <> struct is_unsigned<unsigned long sat accum> : bool_constant<true> {
LIBC_INLINE constexpr operator bool() const { return is_unsigned::value; }
LIBC_INLINE constexpr bool operator()() const { return is_unsigned::value; }
};
#endif // LIBC_COMPILER_HAS_FIXED_POINT

template <typename T>
LIBC_INLINE_VAR constexpr bool is_unsigned_v = is_unsigned<T>::value;

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65 changes: 63 additions & 2 deletions libc/test/src/__support/CPP/type_traits_test.cpp
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Expand Up @@ -6,6 +6,7 @@
//
//===----------------------------------------------------------------------===//

#include "include/llvm-libc-macros/stdfix-macros.h"
#include "src/__support/CPP/type_traits.h"
#include "src/__support/macros/config.h"
#include "test/UnitTest/Test.h"
Expand Down Expand Up @@ -409,7 +410,37 @@ TEST(LlvmLibcTypeTraitsTest, is_object) {

// TODO is_scalar

// TODO is_signed
TEST(LlvmLibcTypeTraitsTest, is_signed) {
EXPECT_TRUE((is_signed_v<int>));
EXPECT_TRUE((is_signed_v<long>));
EXPECT_TRUE((is_signed_v<long long>));
EXPECT_FALSE((is_signed_v<unsigned int>));
EXPECT_FALSE((is_signed_v<unsigned long>));
EXPECT_FALSE((is_signed_v<unsigned long long>));
EXPECT_TRUE((is_signed_v<float>));
EXPECT_TRUE((is_signed_v<double>));
EXPECT_TRUE((is_signed_v<long double>));

#ifdef LIBC_COMPILER_HAS_FIXED_POINT
// for fixed point types
EXPECT_TRUE((is_signed_v<fract>));
EXPECT_FALSE((is_signed_v<unsigned fract>));
EXPECT_TRUE((is_signed_v<accum>));
EXPECT_FALSE((is_signed_v<unsigned accum>));
EXPECT_TRUE((is_signed_v<sat fract>));
EXPECT_FALSE((is_signed_v<unsigned sat fract>));
EXPECT_TRUE((is_signed_v<sat accum>));
EXPECT_FALSE((is_signed_v<unsigned sat accum>));
EXPECT_TRUE((is_signed_v<short fract>));
EXPECT_FALSE((is_signed_v<unsigned short fract>));
EXPECT_TRUE((is_signed_v<short accum>));
EXPECT_FALSE((is_signed_v<unsigned short accum>));
EXPECT_TRUE((is_signed_v<long fract>));
EXPECT_FALSE((is_signed_v<unsigned long fract>));
EXPECT_TRUE((is_signed_v<long accum>));
EXPECT_FALSE((is_signed_v<unsigned long accum>));
#endif
}

// TODO is_trivially_constructible

Expand All @@ -419,7 +450,37 @@ TEST(LlvmLibcTypeTraitsTest, is_object) {

// TODO is_union

// TODO is_unsigned
TEST(LlvmLibcTypeTraitsTest, is_unsigned) {
EXPECT_FALSE((is_unsigned_v<int>));
EXPECT_FALSE((is_unsigned_v<long>));
EXPECT_FALSE((is_unsigned_v<long long>));
EXPECT_TRUE((is_unsigned_v<unsigned int>));
EXPECT_TRUE((is_unsigned_v<unsigned long>));
EXPECT_TRUE((is_unsigned_v<unsigned long long>));
EXPECT_FALSE((is_unsigned_v<float>));
EXPECT_FALSE((is_unsigned_v<double>));
EXPECT_FALSE((is_unsigned_v<long double>));

#ifdef LIBC_COMPILER_HAS_FIXED_POINT
// for fixed point types
EXPECT_FALSE((is_unsigned_v<fract>));
EXPECT_TRUE((is_unsigned_v<unsigned fract>));
EXPECT_FALSE((is_unsigned_v<accum>));
EXPECT_TRUE((is_unsigned_v<unsigned accum>));
EXPECT_FALSE((is_unsigned_v<sat fract>));
EXPECT_TRUE((is_unsigned_v<unsigned sat fract>));
EXPECT_FALSE((is_unsigned_v<sat accum>));
EXPECT_TRUE((is_unsigned_v<unsigned sat accum>));
EXPECT_FALSE((is_unsigned_v<short fract>));
EXPECT_TRUE((is_unsigned_v<unsigned short fract>));
EXPECT_FALSE((is_unsigned_v<short accum>));
EXPECT_TRUE((is_unsigned_v<unsigned short accum>));
EXPECT_FALSE((is_unsigned_v<long fract>));
EXPECT_TRUE((is_unsigned_v<unsigned long fract>));
EXPECT_FALSE((is_unsigned_v<long accum>));
EXPECT_TRUE((is_unsigned_v<unsigned long accum>));
#endif
}

// TODO is_void

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