[libc-commits] [libc] [libc][NFC] Make EXP_MANT_MASK an implementation detail (PR #75621)

Guillaume Chatelet via libc-commits libc-commits at lists.llvm.org
Fri Dec 15 09:33:02 PST 2023


https://github.com/gchatelet updated https://github.com/llvm/llvm-project/pull/75621

>From 2f65694086912908c6ac5f76cf2dccc2fcc06014 Mon Sep 17 00:00:00 2001
From: Guillaume Chatelet <gchatelet at google.com>
Date: Fri, 15 Dec 2023 16:54:35 +0000
Subject: [PATCH 1/2] [libc][NFC] Make EXP_MANT_MASK an implementation detail

This mask is an implementation detail of FPBits and shouldn't really leak outside of it.
I also used this opportunity to document `FloatProperties`.

For now `FloatProperties` is stateless and works on `StorageType` directly whereas `FPBits` is stateful and allows back and forth between FP type and `StorageType`.
---
 libc/src/__support/FPUtil/FPBits.h            |  12 +-
 libc/src/__support/FPUtil/FloatProperties.h   | 176 +++++++++++++-----
 .../__support/FPUtil/x86_64/LongDoubleBits.h  |   1 -
 libc/src/math/generic/acoshf.cpp              |   3 +-
 libc/src/math/generic/asinhf.cpp              |   3 +-
 libc/src/math/generic/atanhf.cpp              |   5 +-
 libc/src/math/generic/exp.cpp                 |   2 +-
 libc/src/math/generic/exp10.cpp               |   2 +-
 libc/src/math/generic/exp2.cpp                |   2 +-
 libc/src/math/generic/expm1.cpp               |   2 +-
 libc/src/math/generic/inv_trigf_utils.h       |   3 +-
 libc/src/math/generic/powf.cpp                |   4 +-
 libc/src/math/generic/sinhf.cpp               |   3 +-
 libc/src/math/generic/tanhf.cpp               |   3 +-
 14 files changed, 152 insertions(+), 69 deletions(-)

diff --git a/libc/src/__support/FPUtil/FPBits.h b/libc/src/__support/FPUtil/FPBits.h
index 7f5dd0fca58d4f..86d80a9af91221 100644
--- a/libc/src/__support/FPUtil/FPBits.h
+++ b/libc/src/__support/FPUtil/FPBits.h
@@ -33,7 +33,11 @@ template <typename T> struct FPBits : private FloatProperties<T> {
                 "FPBits instantiated with invalid type.");
   using typename FloatProperties<T>::StorageType;
   using FloatProperties<T>::TOTAL_LEN;
-  using FloatProperties<T>::EXP_MANT_MASK;
+
+private:
+  using FloatProperties<T>::EXP_SIG_MASK;
+
+public:
   using FloatProperties<T>::EXP_MASK;
   using FloatProperties<T>::EXP_BIAS;
   using FloatProperties<T>::EXP_LEN;
@@ -146,15 +150,15 @@ template <typename T> struct FPBits : private FloatProperties<T> {
   }
 
   LIBC_INLINE constexpr bool is_inf() const {
-    return (bits & EXP_MANT_MASK) == EXP_MASK;
+    return (bits & EXP_SIG_MASK) == EXP_MASK;
   }
 
   LIBC_INLINE constexpr bool is_nan() const {
-    return (bits & EXP_MANT_MASK) > EXP_MASK;
+    return (bits & EXP_SIG_MASK) > EXP_MASK;
   }
 
   LIBC_INLINE constexpr bool is_quiet_nan() const {
-    return (bits & EXP_MANT_MASK) == (EXP_MASK | QUIET_NAN_MASK);
+    return (bits & EXP_SIG_MASK) == (EXP_MASK | QUIET_NAN_MASK);
   }
 
   LIBC_INLINE constexpr bool is_inf_or_nan() const {
diff --git a/libc/src/__support/FPUtil/FloatProperties.h b/libc/src/__support/FPUtil/FloatProperties.h
index 896c29919e2f77..ea1eb5b8b5bbbc 100644
--- a/libc/src/__support/FPUtil/FloatProperties.h
+++ b/libc/src/__support/FPUtil/FloatProperties.h
@@ -28,6 +28,36 @@ enum class FPType {
   X86_Binary80,
 };
 
+// Returns the 'FPType' associated with this 'FP' type.
+template <typename FP> LIBC_INLINE static constexpr FPType get_fp_type() {
+  if constexpr (cpp::is_same_v<FP, float> && __FLT_MANT_DIG__ == 24)
+    return FPType::IEEE754_Binary32;
+  else if constexpr (cpp::is_same_v<FP, double> && __DBL_MANT_DIG__ == 53)
+    return FPType::IEEE754_Binary64;
+  else if constexpr (cpp::is_same_v<FP, long double>) {
+    if constexpr (__LDBL_MANT_DIG__ == 53)
+      return FPType::IEEE754_Binary64;
+    else if constexpr (__LDBL_MANT_DIG__ == 64)
+      return FPType::X86_Binary80;
+    else if constexpr (__LDBL_MANT_DIG__ == 113)
+      return FPType::IEEE754_Binary128;
+  }
+#if defined(LIBC_COMPILER_HAS_C23_FLOAT16)
+  else if constexpr (cpp::is_same_v<FP, _Float16>)
+    return FPType::IEEE754_Binary16;
+#endif
+#if defined(LIBC_COMPILER_HAS_C23_FLOAT128)
+  else if constexpr (cpp::is_same_v<FP, _Float128>)
+    return FPType::IEEE754_Binary128;
+#endif
+#if defined(LIBC_COMPILER_HAS_FLOAT128_EXTENSION)
+  else if constexpr (cpp::is_same_v<FP, __float128>)
+    return FPType::IEEE754_Binary128;
+#endif
+  else
+    static_assert(cpp::always_false<FP>, "Unsupported type");
+}
+
 // For now 'FPEncoding', 'FPBaseProperties' and 'FPCommonProperties' are
 // implementation details.
 namespace internal {
@@ -89,29 +119,56 @@ struct FPProperties : public internal::FPBaseProperties<fp_type> {
   using UP = internal::FPBaseProperties<fp_type>;
 
 public:
-  // The number of bits to represent sign. For documentation purpose, always 1.
-  LIBC_INLINE_VAR static constexpr int SIGN_LEN = 1;
-  using UP::EXP_LEN;   // The number of bits for the *exponent* part
-  using UP::SIG_LEN;   // The number of bits for the *significand* part
-  using UP::TOTAL_LEN; // For convenience, the sum of `SIG_LEN`, `EXP_LEN`,
-                       // and `SIGN_LEN`.
-  static_assert(SIGN_LEN + EXP_LEN + SIG_LEN == TOTAL_LEN);
-
+  //---------------------------------------------------------------------------
+  // Physical layer
+  //
+  // At this level, we only describe the bit *ranges* not necessarily their
+  // meaning. A *floating point number* is composed of three parts : a `sign`,
+  // an `exponent` and a `significand`. By convention, they are also designated
+  // by a single letter : `s`, `e` and `m`. Note that `m` here stands for
+  // *mantissa* but its use is generally discouraged :
+  // https://en.wikipedia.org/wiki/Significand#Terminology
+  //
+  // For virtually all of the floating point number formats the bit ranges are
+  // in this exact order : `sign`, `exponent` and `significand`.
+  //
+  // e.g. Depiction of 'IEEE754 Float16'
+  //
+  // sign   exponent          significand
+  //    |  ┌───────┐  ┌─────────────────┐
+  //    0  0 1 1 0 0  0 1 0 0 0 0 0 0 0 0
+  //   15 14      10  9                 0
+  //
+  //---------------------------------------------------------------------------
+  // Types
+  //---------------------------------------------------------------------------
   // An unsigned integer that is wide enough to contain all of the floating
   // point bits.
   using StorageType = typename UP::StorageType;
 
+  //---------------------------------------------------------------------------
+  // Properties
+  //---------------------------------------------------------------------------
+
   // The number of bits in StorageType.
   LIBC_INLINE_VAR static constexpr int STORAGE_LEN =
       sizeof(StorageType) * CHAR_BIT;
-  static_assert(STORAGE_LEN >= TOTAL_LEN);
 
-  // The exponent bias. Always positive.
-  LIBC_INLINE_VAR static constexpr int32_t EXP_BIAS =
-      (1U << (EXP_LEN - 1U)) - 1U;
-  static_assert(EXP_BIAS > 0);
+  // The number of bits to represent sign. For documentation purpose, always 1.
+  LIBC_INLINE_VAR static constexpr int SIGN_LEN = 1;
+  using UP::EXP_LEN;   // The number of bits for the *exponent* part
+  using UP::SIG_LEN;   // The number of bits for the *significand* part
+  using UP::TOTAL_LEN; // For convenience, the sum of `SIG_LEN`, `EXP_LEN`,
+                       // and `SIGN_LEN`.
+  static_assert(SIGN_LEN + EXP_LEN + SIG_LEN == TOTAL_LEN);
+  static_assert(STORAGE_LEN >= TOTAL_LEN);
 
 private:
+  // Helper to set a single bit at 'position'.
+  LIBC_INLINE static constexpr StorageType bit_at(int position) {
+    return StorageType(1) << position;
+  }
+
   // The shift amount to get the *significand* part to the least significant
   // bit. Always `0` but kept for consistency.
   LIBC_INLINE_VAR static constexpr int SIG_MASK_SHIFT = 0;
@@ -120,17 +177,19 @@ struct FPProperties : public internal::FPBaseProperties<fp_type> {
   // The shift amount to get the *sign* part to the least significant bit.
   LIBC_INLINE_VAR static constexpr int SIGN_MASK_SHIFT = SIG_LEN + EXP_LEN;
 
+public:
   // The bit pattern that keeps only the *significand* part.
   LIBC_INLINE_VAR static constexpr StorageType SIG_MASK =
       mask_trailing_ones<StorageType, SIG_LEN>() << SIG_MASK_SHIFT;
-
-public:
   // The bit pattern that keeps only the *exponent* part.
   LIBC_INLINE_VAR static constexpr StorageType EXP_MASK =
       mask_trailing_ones<StorageType, EXP_LEN>() << EXP_MASK_SHIFT;
   // The bit pattern that keeps only the *sign* part.
   LIBC_INLINE_VAR static constexpr StorageType SIGN_MASK =
       mask_trailing_ones<StorageType, SIGN_LEN>() << SIGN_MASK_SHIFT;
+  // The bit pattern that keeps only the *exponent + significand* part.
+  LIBC_INLINE_VAR static constexpr StorageType EXP_SIG_MASK =
+      mask_trailing_ones<StorageType, EXP_LEN + SIG_LEN>();
   // The bit pattern that keeps only the *sign + exponent + significand* part.
   LIBC_INLINE_VAR static constexpr StorageType FP_MASK =
       mask_trailing_ones<StorageType, TOTAL_LEN>();
@@ -138,11 +197,43 @@ struct FPProperties : public internal::FPBaseProperties<fp_type> {
   static_assert((SIG_MASK & EXP_MASK & SIGN_MASK) == 0, "masks disjoint");
   static_assert((SIG_MASK | EXP_MASK | SIGN_MASK) == FP_MASK, "masks cover");
 
-private:
-  LIBC_INLINE static constexpr StorageType bit_at(int position) {
-    return StorageType(1) << position;
-  }
+  // The exponent bias. Always positive.
+  LIBC_INLINE_VAR static constexpr int32_t EXP_BIAS =
+      (1U << (EXP_LEN - 1U)) - 1U;
+  static_assert(EXP_BIAS > 0);
 
+  //---------------------------------------------------------------------------
+  // Semantic layer
+  //
+  // At this level, we define properties and methods of the floating point
+  // number and regardless of how it's encoded. In this layer, the signficand is
+  // always returned in its normal form and the exponent is always a signed
+  // integer.
+  //
+  // * Normal form : A significand is in a *normalized form* when the leading
+  // `1` is at the position of the most significant bit.
+  //
+  // e.g., Here is the `1.01` normalized significand stored in an `uint16_t`.
+  //    ┌──────────────────────────────┐
+  //     1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0
+  //    15                             0
+  //
+  // It is always possible to normalize a (non-zero) significand by decreasing
+  // its associated exponent. For instance, the value `0.000000000000001p0` can
+  // be rewritten `1p-15`.
+  //
+  // * Significant working format : By definition `StorageType` can store all of
+  // the bits for the floating point format (`sign` + `exponent` +
+  // `significand`). In the Semantic layer we also use the `StorageType` to
+  // manipulate the `significand`, this means that the number of bits for the
+  // fraction part is greater in the Semantic layer than in the underlying
+  // floating point format.
+  //
+  //
+  //---------------------------------------------------------------------------
+  // Properties
+  //---------------------------------------------------------------------------
+private:
   LIBC_INLINE_VAR static constexpr StorageType QNAN_MASK =
       UP::ENCODING == internal::FPEncoding::X86_ExtendedPrecision
           ? bit_at(SIG_LEN - 1) | bit_at(SIG_LEN - 2) // 0b1100...
@@ -152,7 +243,6 @@ struct FPProperties : public internal::FPBaseProperties<fp_type> {
       UP::ENCODING == internal::FPEncoding::X86_ExtendedPrecision
           ? bit_at(SIG_LEN - 1) | bit_at(SIG_LEN - 3) // 0b1010...
           : bit_at(SIG_LEN - 2);                      // 0b0100...
-
 public:
   // The number of bits after the decimal dot when the number is in normal form.
   LIBC_INLINE_VAR static constexpr int FRACTION_LEN =
@@ -162,44 +252,28 @@ struct FPProperties : public internal::FPBaseProperties<fp_type> {
       FRACTION_LEN + 1;
   LIBC_INLINE_VAR static constexpr StorageType FRACTION_MASK =
       mask_trailing_ones<StorageType, FRACTION_LEN>();
-  LIBC_INLINE_VAR static constexpr StorageType EXP_MANT_MASK =
-      EXP_MASK | SIG_MASK;
 
   // If a number x is a NAN, then it is a quiet NAN if:
   //   QuietNaNMask & bits(x) != 0
   // Else, it is a signalling NAN.
   static constexpr StorageType QUIET_NAN_MASK = QNAN_MASK;
-};
 
-//-----------------------------------------------------------------------------
-template <typename FP> LIBC_INLINE static constexpr FPType get_fp_type() {
-  if constexpr (cpp::is_same_v<FP, float> && __FLT_MANT_DIG__ == 24)
-    return FPType::IEEE754_Binary32;
-  else if constexpr (cpp::is_same_v<FP, double> && __DBL_MANT_DIG__ == 53)
-    return FPType::IEEE754_Binary64;
-  else if constexpr (cpp::is_same_v<FP, long double>) {
-    if constexpr (__LDBL_MANT_DIG__ == 53)
-      return FPType::IEEE754_Binary64;
-    else if constexpr (__LDBL_MANT_DIG__ == 64)
-      return FPType::X86_Binary80;
-    else if constexpr (__LDBL_MANT_DIG__ == 113)
-      return FPType::IEEE754_Binary128;
+  //---------------------------------------------------------------------------
+  // Observers
+  //---------------------------------------------------------------------------
+
+  LIBC_INLINE static constexpr bool sign(StorageType value) {
+    return value & SIGN_MASK;
   }
-#if defined(LIBC_COMPILER_HAS_C23_FLOAT16)
-  else if constexpr (cpp::is_same_v<FP, _Float16>)
-    return FPType::IEEE754_Binary16;
-#endif
-#if defined(LIBC_COMPILER_HAS_C23_FLOAT128)
-  else if constexpr (cpp::is_same_v<FP, _Float128>)
-    return FPType::IEEE754_Binary128;
-#endif
-#if defined(LIBC_COMPILER_HAS_FLOAT128_EXTENSION)
-  else if constexpr (cpp::is_same_v<FP, __float128>)
-    return FPType::IEEE754_Binary128;
-#endif
-  else
-    static_assert(cpp::always_false<FP>, "Unsupported type");
-}
+
+  //---------------------------------------------------------------------------
+  // Modifiers
+  //---------------------------------------------------------------------------
+
+  LIBC_INLINE static constexpr StorageType abs(StorageType value) {
+    return value & EXP_SIG_MASK;
+  }
+};
 
 template <typename FP>
 struct FloatProperties : public FPProperties<get_fp_type<FP>()> {};
diff --git a/libc/src/__support/FPUtil/x86_64/LongDoubleBits.h b/libc/src/__support/FPUtil/x86_64/LongDoubleBits.h
index 89c47063ebac4d..b6054b4d61e937 100644
--- a/libc/src/__support/FPUtil/x86_64/LongDoubleBits.h
+++ b/libc/src/__support/FPUtil/x86_64/LongDoubleBits.h
@@ -29,7 +29,6 @@ namespace fputil {
 template <> struct FPBits<long double> : private FloatProperties<long double> {
   using typename FloatProperties<long double>::StorageType;
   using FloatProperties<long double>::TOTAL_LEN;
-  using FloatProperties<long double>::EXP_MANT_MASK;
   using FloatProperties<long double>::EXP_MASK;
   using FloatProperties<long double>::EXP_BIAS;
   using FloatProperties<long double>::EXP_LEN;
diff --git a/libc/src/math/generic/acoshf.cpp b/libc/src/math/generic/acoshf.cpp
index 142c17795d083a..708653a5c5f7ce 100644
--- a/libc/src/math/generic/acoshf.cpp
+++ b/libc/src/math/generic/acoshf.cpp
@@ -20,6 +20,7 @@ namespace LIBC_NAMESPACE {
 
 LLVM_LIBC_FUNCTION(float, acoshf, (float x)) {
   using FPBits_t = typename fputil::FPBits<float>;
+  using FloatProp = typename fputil::FloatProperties<float>;
   FPBits_t xbits(x);
   uint32_t x_u = xbits.uintval();
 
@@ -34,7 +35,7 @@ LLVM_LIBC_FUNCTION(float, acoshf, (float x)) {
 
   if (LIBC_UNLIKELY(x_u >= 0x4f8ffb03)) {
     // Check for exceptional values.
-    uint32_t x_abs = x_u & FPBits_t::EXP_MANT_MASK;
+    uint32_t x_abs = FloatProp::abs(x_u);
     if (LIBC_UNLIKELY(x_abs >= 0x7f80'0000U)) {
       // x is +inf or NaN.
       return x;
diff --git a/libc/src/math/generic/asinhf.cpp b/libc/src/math/generic/asinhf.cpp
index 5b2f63d3fe144e..07adfadc280791 100644
--- a/libc/src/math/generic/asinhf.cpp
+++ b/libc/src/math/generic/asinhf.cpp
@@ -19,9 +19,10 @@ namespace LIBC_NAMESPACE {
 
 LLVM_LIBC_FUNCTION(float, asinhf, (float x)) {
   using FPBits_t = typename fputil::FPBits<float>;
+  using FloatProp = typename fputil::FloatProperties<float>;
   FPBits_t xbits(x);
   uint32_t x_u = xbits.uintval();
-  uint32_t x_abs = x_u & FPBits_t::EXP_MANT_MASK;
+  uint32_t x_abs = FloatProp::abs(x_u);
 
   // |x| <= 2^-3
   if (LIBC_UNLIKELY(x_abs <= 0x3e80'0000U)) {
diff --git a/libc/src/math/generic/atanhf.cpp b/libc/src/math/generic/atanhf.cpp
index dfec28e9a44a72..ac609d0d1c8d71 100644
--- a/libc/src/math/generic/atanhf.cpp
+++ b/libc/src/math/generic/atanhf.cpp
@@ -15,9 +15,10 @@ namespace LIBC_NAMESPACE {
 
 LLVM_LIBC_FUNCTION(float, atanhf, (float x)) {
   using FPBits = typename fputil::FPBits<float>;
+  using FloatProp = typename fputil::FloatProperties<float>;
   FPBits xbits(x);
-  bool sign = xbits.get_sign();
-  uint32_t x_abs = xbits.uintval() & FPBits::EXP_MANT_MASK;
+  bool sign = FloatProp::sign(xbits.uintval());
+  uint32_t x_abs = FloatProp::abs(xbits.uintval());
 
   // |x| >= 1.0
   if (LIBC_UNLIKELY(x_abs >= 0x3F80'0000U)) {
diff --git a/libc/src/math/generic/exp.cpp b/libc/src/math/generic/exp.cpp
index ebfd14dd6cc166..badef28f6c0278 100644
--- a/libc/src/math/generic/exp.cpp
+++ b/libc/src/math/generic/exp.cpp
@@ -178,7 +178,7 @@ double set_exceptional(double x) {
   FPBits xbits(x);
 
   uint64_t x_u = xbits.uintval();
-  uint64_t x_abs = x_u & FloatProp::EXP_MANT_MASK;
+  uint64_t x_abs = FloatProp::abs(x_u);
 
   // |x| <= 2^-53
   if (x_abs <= 0x3ca0'0000'0000'0000ULL) {
diff --git a/libc/src/math/generic/exp10.cpp b/libc/src/math/generic/exp10.cpp
index 4e1babcee541bd..07df55d1ad7145 100644
--- a/libc/src/math/generic/exp10.cpp
+++ b/libc/src/math/generic/exp10.cpp
@@ -225,7 +225,7 @@ double set_exceptional(double x) {
   FPBits xbits(x);
 
   uint64_t x_u = xbits.uintval();
-  uint64_t x_abs = x_u & FloatProp::EXP_MANT_MASK;
+  uint64_t x_abs = FloatProp::abs( x_u);
 
   // |x| < log10(1 + 2^-53)
   if (x_abs <= 0x3c8bcb7b1526e50e) {
diff --git a/libc/src/math/generic/exp2.cpp b/libc/src/math/generic/exp2.cpp
index 07691ca0e7b62a..7574f1777d27c6 100644
--- a/libc/src/math/generic/exp2.cpp
+++ b/libc/src/math/generic/exp2.cpp
@@ -200,7 +200,7 @@ double set_exceptional(double x) {
   FPBits xbits(x);
 
   uint64_t x_u = xbits.uintval();
-  uint64_t x_abs = x_u & FloatProp::EXP_MANT_MASK;
+  uint64_t x_abs = FloatProp::abs(x_u);
 
   // |x| < log2(1 + 2^-53)
   if (x_abs <= 0x3ca71547652b82fd) {
diff --git a/libc/src/math/generic/expm1.cpp b/libc/src/math/generic/expm1.cpp
index a0d47f00828ce4..3114eeb056137e 100644
--- a/libc/src/math/generic/expm1.cpp
+++ b/libc/src/math/generic/expm1.cpp
@@ -223,7 +223,7 @@ double set_exceptional(double x) {
   FPBits xbits(x);
 
   uint64_t x_u = xbits.uintval();
-  uint64_t x_abs = x_u & FloatProp::EXP_MANT_MASK;
+  uint64_t x_abs = FloatProp::abs( x_u);
 
   // |x| <= 2^-53.
   if (x_abs <= 0x3ca0'0000'0000'0000ULL) {
diff --git a/libc/src/math/generic/inv_trigf_utils.h b/libc/src/math/generic/inv_trigf_utils.h
index 588ebbfa71aeb0..600b3a3ccd8924 100644
--- a/libc/src/math/generic/inv_trigf_utils.h
+++ b/libc/src/math/generic/inv_trigf_utils.h
@@ -38,6 +38,7 @@ extern const double ATAN_K[5];
 // x should be positive, normal finite value
 LIBC_INLINE double atan_eval(double x) {
   using FPB = fputil::FPBits<double>;
+  using FloatProp = fputil::FloatProperties<double>;
   // Added some small value to umin and umax mantissa to avoid possible rounding
   // errors.
   FPB::StorageType umin =
@@ -50,7 +51,7 @@ LIBC_INLINE double atan_eval(double x) {
 
   FPB bs(x);
   bool sign = bs.get_sign();
-  auto x_abs = bs.uintval() & FPB::EXP_MANT_MASK;
+  auto x_abs = FloatProp::abs(bs.uintval());
 
   if (x_abs <= umin) {
     double pe = LIBC_NAMESPACE::fputil::polyeval(
diff --git a/libc/src/math/generic/powf.cpp b/libc/src/math/generic/powf.cpp
index dd7fa7f6115d4e..a4d29a2c31dcd4 100644
--- a/libc/src/math/generic/powf.cpp
+++ b/libc/src/math/generic/powf.cpp
@@ -517,9 +517,9 @@ LLVM_LIBC_FUNCTION(float, powf, (float x, float y)) {
   FloatBits xbits(x), ybits(y);
 
   uint32_t x_u = xbits.uintval();
-  uint32_t x_abs = x_u & FloatProp::EXP_MANT_MASK;
+  uint32_t x_abs = FloatProp::abs(x_u);
   uint32_t y_u = ybits.uintval();
-  uint32_t y_abs = y_u & FloatProp::EXP_MANT_MASK;
+  uint32_t y_abs = FloatProp::abs(y_u);
 
   ///////// BEGIN - Check exceptional cases ////////////////////////////////////
 
diff --git a/libc/src/math/generic/sinhf.cpp b/libc/src/math/generic/sinhf.cpp
index db6794620b068c..fc5e760f269faa 100644
--- a/libc/src/math/generic/sinhf.cpp
+++ b/libc/src/math/generic/sinhf.cpp
@@ -16,8 +16,9 @@ namespace LIBC_NAMESPACE {
 
 LLVM_LIBC_FUNCTION(float, sinhf, (float x)) {
   using FPBits = typename fputil::FPBits<float>;
+  using FloatProp = typename fputil::FloatProperties<float>;
   FPBits xbits(x);
-  uint32_t x_abs = xbits.uintval() & FPBits::EXP_MANT_MASK;
+  uint32_t x_abs = FloatProp::abs(xbits.uintval());
 
   // When |x| >= 90, or x is inf or nan
   if (LIBC_UNLIKELY(x_abs >= 0x42b4'0000U || x_abs <= 0x3da0'0000U)) {
diff --git a/libc/src/math/generic/tanhf.cpp b/libc/src/math/generic/tanhf.cpp
index 9042a41c5ed3fe..71ed6097b039db 100644
--- a/libc/src/math/generic/tanhf.cpp
+++ b/libc/src/math/generic/tanhf.cpp
@@ -22,9 +22,10 @@ constexpr double LOG2_E_EXP2_6 = ExpBase::LOG2_B * 2.0;
 
 LLVM_LIBC_FUNCTION(float, tanhf, (float x)) {
   using FPBits = typename fputil::FPBits<float>;
+  using FloatProp = typename fputil::FloatProperties<float>;
   FPBits xbits(x);
   uint32_t x_u = xbits.uintval();
-  uint32_t x_abs = x_u & FPBits::EXP_MANT_MASK;
+  uint32_t x_abs = FloatProp::abs(x_u);
 
   // When |x| >= 15, or x is inf or nan, or |x| <= 0.078125
   if (LIBC_UNLIKELY((x_abs >= 0x4170'0000U) || (x_abs <= 0x3da0'0000U))) {

>From c2bf7ae2ea8719a80cf38d815597063d7e57210c Mon Sep 17 00:00:00 2001
From: Guillaume Chatelet <gchatelet at google.com>
Date: Fri, 15 Dec 2023 17:32:47 +0000
Subject: [PATCH 2/2] fix formmatting

---
 libc/src/math/generic/exp10.cpp | 2 +-
 libc/src/math/generic/expm1.cpp | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/libc/src/math/generic/exp10.cpp b/libc/src/math/generic/exp10.cpp
index 07df55d1ad7145..3c6e29b37448a9 100644
--- a/libc/src/math/generic/exp10.cpp
+++ b/libc/src/math/generic/exp10.cpp
@@ -225,7 +225,7 @@ double set_exceptional(double x) {
   FPBits xbits(x);
 
   uint64_t x_u = xbits.uintval();
-  uint64_t x_abs = FloatProp::abs( x_u);
+  uint64_t x_abs = FloatProp::abs(x_u);
 
   // |x| < log10(1 + 2^-53)
   if (x_abs <= 0x3c8bcb7b1526e50e) {
diff --git a/libc/src/math/generic/expm1.cpp b/libc/src/math/generic/expm1.cpp
index 3114eeb056137e..00ae6743e6b4ab 100644
--- a/libc/src/math/generic/expm1.cpp
+++ b/libc/src/math/generic/expm1.cpp
@@ -223,7 +223,7 @@ double set_exceptional(double x) {
   FPBits xbits(x);
 
   uint64_t x_u = xbits.uintval();
-  uint64_t x_abs = FloatProp::abs( x_u);
+  uint64_t x_abs = FloatProp::abs(x_u);
 
   // |x| <= 2^-53.
   if (x_abs <= 0x3ca0'0000'0000'0000ULL) {



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