diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index 7a615809ed55cd..2b5b12926cb623 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -22,6 +22,7 @@ set(TARGET_LIBM_ENTRYPOINTS
     libc.src.math.exp2f
     libc.src.math.fabs
     libc.src.math.fabsf
+    libc.src.math.fabsl
     libc.src.math.floor
     libc.src.math.floorf
     libc.src.math.frexp
@@ -36,4 +37,5 @@ set(TARGET_LIBM_ENTRYPOINTS
     libc.src.math.sinf
     libc.src.math.trunc
     libc.src.math.truncf
+    libc.src.math.truncl
 )
diff --git a/libc/config/linux/api.td b/libc/config/linux/api.td
index f2b7050661d370..79fdb15412caf9 100644
--- a/libc/config/linux/api.td
+++ b/libc/config/linux/api.td
@@ -157,6 +157,7 @@ def MathAPI : PublicAPI<"math.h"> {
    "cosf",
    "fabs",
    "fabsf",
+   "fabsl",
    "floor",
    "floorf",
    "frexp",
@@ -173,6 +174,7 @@ def MathAPI : PublicAPI<"math.h"> {
    "sinf",
    "trunc",
    "truncf",
+   "truncl",
   ];
 }
 
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 93b0dfdcb3f38b..656ccddfeedf1f 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -54,6 +54,7 @@ set(TARGET_LIBM_ENTRYPOINTS
     libc.src.math.exp2f
     libc.src.math.fabs
     libc.src.math.fabsf
+    libc.src.math.fabsl
     libc.src.math.floor
     libc.src.math.floorf
     libc.src.math.frexp
@@ -68,4 +69,5 @@ set(TARGET_LIBM_ENTRYPOINTS
     libc.src.math.sinf
     libc.src.math.trunc
     libc.src.math.truncf
+    libc.src.math.truncl
 )
diff --git a/libc/spec/stdc.td b/libc/spec/stdc.td
index b31f89d3d73a95..998a63c6a02f8a 100644
--- a/libc/spec/stdc.td
+++ b/libc/spec/stdc.td
@@ -197,6 +197,7 @@ def StdC : StandardSpec<"stdc"> {
 
           FunctionSpec<"fabs", RetValSpec<DoubleType>, [ArgSpec<DoubleType>]>,
           FunctionSpec<"fabsf", RetValSpec<FloatType>, [ArgSpec<FloatType>]>,
+          FunctionSpec<"fabsl", RetValSpec<LongDoubleType>, [ArgSpec<LongDoubleType>]>,
 
           FunctionSpec<"floor", RetValSpec<DoubleType>, [ArgSpec<DoubleType>]>,
           FunctionSpec<"floorf", RetValSpec<FloatType>, [ArgSpec<FloatType>]>,
@@ -221,6 +222,7 @@ def StdC : StandardSpec<"stdc"> {
 
           FunctionSpec<"trunc", RetValSpec<DoubleType>, [ArgSpec<DoubleType>]>,
           FunctionSpec<"truncf", RetValSpec<FloatType>, [ArgSpec<FloatType>]>,
+          FunctionSpec<"truncl", RetValSpec<LongDoubleType>, [ArgSpec<LongDoubleType>]>,
       ]
   >;
 
diff --git a/libc/src/math/CMakeLists.txt b/libc/src/math/CMakeLists.txt
index c74e7e4ab5ffd0..0d673e086097fe 100644
--- a/libc/src/math/CMakeLists.txt
+++ b/libc/src/math/CMakeLists.txt
@@ -64,6 +64,8 @@ add_entrypoint_object(
     fabs.h
   DEPENDS
     libc.utils.FPUtil.fputil
+  COMPILE_OPTIONS
+    -O2
 )
 
 add_entrypoint_object(
@@ -74,6 +76,20 @@ add_entrypoint_object(
     fabsf.h
   DEPENDS
     libc.utils.FPUtil.fputil
+  COMPILE_OPTIONS
+    -O2
+)
+
+add_entrypoint_object(
+  fabsl
+  SRCS
+    fabsl.cpp
+  HDRS
+    fabsl.h
+  DEPENDS
+    libc.utils.FPUtil.fputil
+  COMPILE_OPTIONS
+    -O2
 )
 
 add_entrypoint_object(
@@ -84,6 +100,8 @@ add_entrypoint_object(
     trunc.h
   DEPENDS
     libc.utils.FPUtil.fputil
+  COMPILE_OPTIONS
+    -O2
 )
 
 add_entrypoint_object(
@@ -94,6 +112,20 @@ add_entrypoint_object(
     truncf.h
   DEPENDS
     libc.utils.FPUtil.fputil
+  COMPILE_OPTIONS
+    -O2
+)
+
+add_entrypoint_object(
+  truncl
+  SRCS
+    truncl.cpp
+  HDRS
+    truncl.h
+  DEPENDS
+    libc.utils.FPUtil.fputil
+  COMPILE_OPTIONS
+    -O2
 )
 
 add_entrypoint_object(
@@ -104,6 +136,8 @@ add_entrypoint_object(
     ceil.h
   DEPENDS
     libc.utils.FPUtil.fputil
+  COMPILE_OPTIONS
+    -O2
 )
 
 add_entrypoint_object(
@@ -114,6 +148,8 @@ add_entrypoint_object(
     ceilf.h
   DEPENDS
     libc.utils.FPUtil.fputil
+  COMPILE_OPTIONS
+    -O2
 )
 
 add_entrypoint_object(
@@ -124,6 +160,8 @@ add_entrypoint_object(
     floor.h
   DEPENDS
     libc.utils.FPUtil.fputil
+  COMPILE_OPTIONS
+    -O2
 )
 
 add_entrypoint_object(
@@ -134,6 +172,8 @@ add_entrypoint_object(
     floorf.h
   DEPENDS
     libc.utils.FPUtil.fputil
+  COMPILE_OPTIONS
+    -O2
 )
 
 add_entrypoint_object(
diff --git a/libc/src/math/fabsl.cpp b/libc/src/math/fabsl.cpp
new file mode 100644
index 00000000000000..6e8f72873a253b
--- /dev/null
+++ b/libc/src/math/fabsl.cpp
@@ -0,0 +1,18 @@
+//===-- Implementation of fabsf function ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/__support/common.h"
+#include "utils/FPUtil/BasicOperations.h"
+
+namespace __llvm_libc {
+
+long double LLVM_LIBC_ENTRYPOINT(fabsl)(long double x) {
+  return fputil::abs(x);
+}
+
+} // namespace __llvm_libc
diff --git a/libc/src/math/fabsl.h b/libc/src/math/fabsl.h
new file mode 100644
index 00000000000000..fa25b1ab564d7d
--- /dev/null
+++ b/libc/src/math/fabsl.h
@@ -0,0 +1,18 @@
+//===-- Implementation header for fabsf -------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_MATH_FABSL_H
+#define LLVM_LIBC_SRC_MATH_FABSL_H
+
+namespace __llvm_libc {
+
+long double fabsl(long double x);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_MATH_FABSL_H
diff --git a/libc/src/math/truncl.cpp b/libc/src/math/truncl.cpp
new file mode 100644
index 00000000000000..0eb557a804f47c
--- /dev/null
+++ b/libc/src/math/truncl.cpp
@@ -0,0 +1,18 @@
+//===-- Implementation of truncl function ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/__support/common.h"
+#include "utils/FPUtil/NearestIntegerOperations.h"
+
+namespace __llvm_libc {
+
+long double LLVM_LIBC_ENTRYPOINT(truncl)(long double x) {
+  return fputil::trunc(x);
+}
+
+} // namespace __llvm_libc
diff --git a/libc/src/math/truncl.h b/libc/src/math/truncl.h
new file mode 100644
index 00000000000000..2a78ffaa3c5ef7
--- /dev/null
+++ b/libc/src/math/truncl.h
@@ -0,0 +1,18 @@
+//===-- Implementation header for truncl ------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_MATH_TRUNCL_H
+#define LLVM_LIBC_SRC_MATH_TRUNCL_H
+
+namespace __llvm_libc {
+
+long double truncl(long double x);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_MATH_TRUNCL_H
diff --git a/libc/test/src/math/CMakeLists.txt b/libc/test/src/math/CMakeLists.txt
index ebc03d3452cc7c..1617905150e59c 100644
--- a/libc/test/src/math/CMakeLists.txt
+++ b/libc/test/src/math/CMakeLists.txt
@@ -97,6 +97,19 @@ add_math_unittest(
     libc.utils.FPUtil.fputil
 )
 
+add_math_unittest(
+  fabsl_test
+  NEED_MPFR
+  SUITE
+    libc_math_unittests
+  SRCS
+    fabsl_test.cpp
+  DEPENDS
+    libc.include.math
+    libc.src.math.fabsl
+    libc.utils.FPUtil.fputil
+)
+
 add_math_unittest(
   trunc_test
   NEED_MPFR
@@ -123,6 +136,19 @@ add_math_unittest(
     libc.utils.FPUtil.fputil
 )
 
+add_math_unittest(
+  truncl_test
+  NEED_MPFR
+  SUITE
+    libc_math_unittests
+  SRCS
+    truncl_test.cpp
+  DEPENDS
+    libc.include.math
+    libc.src.math.truncl
+    libc.utils.FPUtil.fputil
+)
+
 add_math_unittest(
   ceil_test
   NEED_MPFR
diff --git a/libc/test/src/math/fabsl_test.cpp b/libc/test/src/math/fabsl_test.cpp
new file mode 100644
index 00000000000000..4a645682446abc
--- /dev/null
+++ b/libc/test/src/math/fabsl_test.cpp
@@ -0,0 +1,46 @@
+//===-- Unittests for fabsl -----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "include/math.h"
+#include "src/math/fabsl.h"
+#include "utils/FPUtil/FPBits.h"
+#include "utils/MPFRWrapper/MPFRUtils.h"
+#include "utils/UnitTest/Test.h"
+
+using FPBits = __llvm_libc::fputil::FPBits<long double>;
+
+namespace mpfr = __llvm_libc::testing::mpfr;
+
+// Zero tolerance; As in, exact match with MPFR result.
+static constexpr mpfr::Tolerance tolerance{mpfr::Tolerance::floatPrecision, 0,
+                                           0};
+
+TEST(FabslTest, SpecialNumbers) {
+  EXPECT_TRUE(FPBits::zero() == __llvm_libc::fabsl(FPBits::zero()));
+  EXPECT_TRUE(FPBits::zero() == __llvm_libc::fabsl(FPBits::negZero()));
+
+  EXPECT_TRUE(FPBits::inf() == __llvm_libc::fabsl(FPBits::inf()));
+  EXPECT_TRUE(FPBits::inf() == __llvm_libc::fabsl(FPBits::negInf()));
+
+  long double nan = FPBits::buildNaN(1);
+  ASSERT_TRUE(isnan(nan) != 0);
+  ASSERT_TRUE(isnan(__llvm_libc::fabsl(nan)) != 0);
+}
+
+TEST(FabslTest, InLongDoubleRange) {
+  using UIntType = FPBits::UIntType;
+  constexpr UIntType count = 10000000;
+  constexpr UIntType step = UIntType(-1) / count;
+  for (UIntType i = 0, v = 0; i <= count; ++i, v += step) {
+    long double x = FPBits(v);
+    if (isnan(x) || isinf(x))
+      continue;
+    ASSERT_MPFR_MATCH(mpfr::Operation::Abs, x, __llvm_libc::fabsl(x),
+                      tolerance);
+  }
+}
diff --git a/libc/test/src/math/truncl_test.cpp b/libc/test/src/math/truncl_test.cpp
new file mode 100644
index 00000000000000..37f9be74eb4252
--- /dev/null
+++ b/libc/test/src/math/truncl_test.cpp
@@ -0,0 +1,65 @@
+//===-- Unittests for truncl ----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "include/math.h"
+#include "src/math/truncl.h"
+#include "utils/FPUtil/FPBits.h"
+#include "utils/MPFRWrapper/MPFRUtils.h"
+#include "utils/UnitTest/Test.h"
+
+using FPBits = __llvm_libc::fputil::FPBits<long double>;
+
+namespace mpfr = __llvm_libc::testing::mpfr;
+
+// Zero tolerance; As in, exact match with MPFR result.
+static constexpr mpfr::Tolerance tolerance{mpfr::Tolerance::floatPrecision, 0,
+                                           0};
+
+TEST(TrunclTest, SpecialNumbers) {
+  ASSERT_TRUE(FPBits::zero() == __llvm_libc::truncl(FPBits::zero()));
+  ASSERT_TRUE(FPBits::negZero() == __llvm_libc::truncl(FPBits::negZero()));
+
+  ASSERT_TRUE(FPBits::inf() == __llvm_libc::truncl(FPBits::inf()));
+  ASSERT_TRUE(FPBits::negInf() == __llvm_libc::truncl(FPBits::negInf()));
+
+  long double nan = FPBits::buildNaN(1);
+  ASSERT_TRUE(isnan(nan) != 0);
+  ASSERT_TRUE(isnan(__llvm_libc::truncl(nan)) != 0);
+}
+
+TEST(TrunclTest, RoundedNumbers) {
+  ASSERT_TRUE(FPBits(1.0l) == __llvm_libc::truncl(1.0l));
+  ASSERT_TRUE(FPBits(-1.0l) == __llvm_libc::truncl(-1.0l));
+  ASSERT_TRUE(FPBits(10.0l) == __llvm_libc::truncl(10.0l));
+  ASSERT_TRUE(FPBits(-10.0l) == __llvm_libc::truncl(-10.0l));
+  ASSERT_TRUE(FPBits(1234.0l) == __llvm_libc::truncl(1234.0l));
+  ASSERT_TRUE(FPBits(-1234.0l) == __llvm_libc::truncl(-1234.0l));
+}
+
+TEST(TrunclTest, Fractions) {
+  ASSERT_TRUE(FPBits(1.0l) == __llvm_libc::truncl(1.5l));
+  ASSERT_TRUE(FPBits(-1.0l) == __llvm_libc::truncl(-1.75l));
+  ASSERT_TRUE(FPBits(10.0l) == __llvm_libc::truncl(10.32l));
+  ASSERT_TRUE(FPBits(-10.0l) == __llvm_libc::truncl(-10.65l));
+  ASSERT_TRUE(FPBits(1234.0l) == __llvm_libc::truncl(1234.78l));
+  ASSERT_TRUE(FPBits(-1234.0l) == __llvm_libc::truncl(-1234.96l));
+}
+
+TEST(TrunclTest, InLongDoubleRange) {
+  using UIntType = FPBits::UIntType;
+  constexpr UIntType count = 10000000;
+  constexpr UIntType step = UIntType(-1) / count;
+  for (UIntType i = 0, v = 0; i <= count; ++i, v += step) {
+    long double x = FPBits(v);
+    if (isnan(x) || isinf(x))
+      continue;
+
+    ASSERT_MPFR_MATCH(mpfr::Operation::Trunc, x, __llvm_libc::truncl(x),
+                      tolerance);
+  }
+}
diff --git a/libc/utils/FPUtil/BasicOperations.h b/libc/utils/FPUtil/BasicOperations.h
index d5c7004f8bc993..70c0bb557cce62 100644
--- a/libc/utils/FPUtil/BasicOperations.h
+++ b/libc/utils/FPUtil/BasicOperations.h
@@ -6,7 +6,12 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "FloatOperations.h"
+#ifndef LLVM_LIBC_UTILS_FPUTIL_BASIC_OPERATIONS_H
+#define LLVM_LIBC_UTILS_FPUTIL_BASIC_OPERATIONS_H
+
+#include "FPBits.h"
+
+#include "utils/CPP/TypeTraits.h"
 
 namespace __llvm_libc {
 namespace fputil {
@@ -14,8 +19,12 @@ namespace fputil {
 template <typename T,
           cpp::EnableIfType<cpp::IsFloatingPointType<T>::Value, int> = 0>
 static inline T abs(T x) {
-  return valueFromBits(absBits(x));
+  FPBits<T> bits(x);
+  bits.sign = 0;
+  return T(bits);
 }
 
 } // namespace fputil
 } // namespace __llvm_libc
+
+#endif // LLVM_LIBC_UTILS_FPUTIL_BASIC_OPERATIONS_H
diff --git a/libc/utils/FPUtil/CMakeLists.txt b/libc/utils/FPUtil/CMakeLists.txt
index 21013ee1771f7d..d9084f72e84106 100644
--- a/libc/utils/FPUtil/CMakeLists.txt
+++ b/libc/utils/FPUtil/CMakeLists.txt
@@ -1,10 +1,18 @@
+if(${LIBC_TARGET_MACHINE} MATCHES "^x86.*")
+  set(LONG_DOUBLE_HDR LongDoubleBitsX86.h)
+else()
+  set(LONG_DOUBLE_HDR)
+endif()
+
 add_header_library(
   fputil
   HDRS
+    ${LONG_DOUBLE_HDR}
     BitPatterns.h
     FloatOperations.h
     FloatProperties.h
+    FPBits.h
     ManipulationFunctions.h
-  DEPS
+  DEPENDS
     libc.utils.CPP.standalone_cpp
 )
diff --git a/libc/utils/FPUtil/FPBits.h b/libc/utils/FPUtil/FPBits.h
new file mode 100644
index 00000000000000..2c630dba2af76c
--- /dev/null
+++ b/libc/utils/FPUtil/FPBits.h
@@ -0,0 +1,148 @@
+//===-- Abstract class for bit manipulation of float numbers. ---*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_UTILS_FPUTIL_FP_BITS_H
+#define LLVM_LIBC_UTILS_FPUTIL_FP_BITS_H
+
+#include "utils/CPP/TypeTraits.h"
+
+#include <stdint.h>
+
+namespace __llvm_libc {
+namespace fputil {
+
+template <typename T> struct MantissaWidth {};
+template <> struct MantissaWidth<float> {
+  static constexpr unsigned value = 23;
+};
+template <> struct MantissaWidth<double> {
+  static constexpr unsigned value = 52;
+};
+
+template <typename T> struct ExponentWidth {};
+template <> struct ExponentWidth<float> {
+  static constexpr unsigned value = 8;
+};
+template <> struct ExponentWidth<double> {
+  static constexpr unsigned value = 11;
+};
+template <> struct ExponentWidth<long double> {
+  static constexpr unsigned value = 15;
+};
+
+template <typename T> struct FPUIntType {};
+template <> struct FPUIntType<float> { using Type = uint32_t; };
+template <> struct FPUIntType<double> { using Type = uint64_t; };
+
+#if !(defined(__x86_64__) || defined(__i386__))
+// TODO: This has to be extended for visual studio where long double and
+// double are equivalent.
+template <> struct MantissaWidth<long double> {
+  static constexpr unsigned value = 112;
+};
+
+template <> struct FPUIntType<long double> { using Type = __uint128_t; };
+#endif
+
+// A generic class to represent single precision, double precision, and quad
+// precision IEEE 754 floating point formats.
+// On most platforms, the 'float' type corresponds to single precision floating
+// point numbers, the 'double' type corresponds to double precision floating
+// point numers, and the 'long double' type corresponds to the quad precision
+// floating numbers. On x86 platforms however, the 'long double' type maps to
+// an x87 floating point format. This format is an IEEE 754 extension format.
+// It is handled as an explicit specialization of this class.
+template <typename T> struct __attribute__((packed)) FPBits {
+  static_assert(cpp::IsFloatingPointType<T>::Value,
+                "FPBits instantiated with invalid type.");
+
+  // Reinterpreting bits as an integer value and interpreting the bits of an
+  // integer value as a floating point value is used in tests. So, a convenient
+  // type is provided for such reinterpretations.
+  using UIntType = typename FPUIntType<T>::Type;
+
+  UIntType mantissa : MantissaWidth<T>::value;
+  uint16_t exponent : ExponentWidth<T>::value;
+  uint8_t sign : 1;
+
+  static constexpr int exponentBias = (1 << (ExponentWidth<T>::value - 1)) - 1;
+  static constexpr int maxExponent = (1 << ExponentWidth<T>::value) - 1;
+
+  // We don't want accidental type promotions/conversions so we require exact
+  // type match.
+  template <typename XType,
+            cpp::EnableIfType<cpp::IsSame<T, XType>::Value, int> = 0>
+  explicit FPBits(XType x) {
+    *this = *reinterpret_cast<FPBits<T> *>(&x);
+  }
+
+  operator T() { return *reinterpret_cast<T *>(this); }
+
+  int getExponent() const { return int(exponent) - exponentBias; }
+
+  bool isZero() const { return mantissa == 0 && exponent == 0; }
+
+  bool isInf() const { return mantissa == 0 && exponent == maxExponent; }
+
+  bool isNaN() const { return exponent == maxExponent && mantissa != 0; }
+
+  bool isInfOrNaN() const { return exponent == maxExponent; }
+
+  // Methods below this are used by tests.
+  // The to and from integer bits converters are only used in tests. Hence,
+  // the potential software implementations of UIntType will not slow real
+  // code.
+
+  template <typename XType,
+            cpp::EnableIfType<cpp::IsSame<UIntType, XType>::Value, int> = 0>
+  explicit FPBits<long double>(XType x) {
+    // The last 4 bytes of v are ignored in case of i386.
+    *this = *reinterpret_cast<FPBits<T> *>(&x);
+  }
+
+  UIntType bitsAsUInt() const {
+    return *reinterpret_cast<const UIntType *>(this);
+  }
+
+  static FPBits<T> zero() { return FPBits(T(0.0)); }
+
+  static FPBits<T> negZero() {
+    FPBits<T> bits(T(0.0));
+    bits.sign = 1;
+    return bits;
+  }
+
+  static FPBits<T> inf() {
+    FPBits<T> bits(T(0.0));
+    bits.exponent = maxExponent;
+    return bits;
+  }
+
+  static FPBits<T> negInf() {
+    FPBits<T> bits(T(0.0));
+    bits.exponent = maxExponent;
+    bits.sign = 1;
+    return bits;
+  }
+
+  static T buildNaN(UIntType v) {
+    FPBits<T> bits(T(0.0));
+    bits.exponent = maxExponent;
+    bits.mantissa = v;
+    return bits;
+  }
+};
+
+} // namespace fputil
+} // namespace __llvm_libc
+
+#if defined(__x86_64__) || defined(__i386__)
+#include "utils/FPUtil/LongDoubleBitsX86.h"
+#endif
+
+#endif // LLVM_LIBC_UTILS_FPUTIL_FP_BITS_H
diff --git a/libc/utils/FPUtil/FloatOperations.h b/libc/utils/FPUtil/FloatOperations.h
index 0739548f567d60..ffd138d6cc9bd0 100644
--- a/libc/utils/FPUtil/FloatOperations.h
+++ b/libc/utils/FPUtil/FloatOperations.h
@@ -57,7 +57,6 @@ static inline int getExponent(T x) {
   return getExponentFromBits(valueAsBits(x));
 }
 
-
 } // namespace fputil
 } // namespace __llvm_libc
 
diff --git a/libc/utils/FPUtil/LongDoubleBitsX86.h b/libc/utils/FPUtil/LongDoubleBitsX86.h
new file mode 100644
index 00000000000000..1e92dba4383df3
--- /dev/null
+++ b/libc/utils/FPUtil/LongDoubleBitsX86.h
@@ -0,0 +1,127 @@
+//===-- Bit representation of x86 long double numbers -----------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_UTILS_FPUTIL_LONG_DOUBLE_BITS_X86_H
+#define LLVM_LIBC_UTILS_FPUTIL_LONG_DOUBLE_BITS_X86_H
+
+#include "utils/FPUtil/FPBits.h"
+
+#include <stdint.h>
+
+namespace __llvm_libc {
+namespace fputil {
+
+template <> struct MantissaWidth<long double> {
+  static constexpr unsigned value = 63;
+};
+
+template <unsigned Width> struct Padding;
+
+// i386 padding.
+template <> struct Padding<4> { static constexpr unsigned Value = 16; };
+
+// x86_64 padding.
+template <> struct Padding<8> { static constexpr unsigned Value = 48; };
+
+template <> struct __attribute__((packed)) FPBits<long double> {
+  using UIntType = __uint128_t;
+
+  static constexpr int exponentBias = 0x3FFF;
+  static constexpr int maxExponent = 0x7FFF;
+
+  UIntType mantissa : MantissaWidth<long double>::value;
+  uint8_t implicitBit : 1;
+  uint16_t exponent : ExponentWidth<long double>::value;
+  uint8_t sign : 1;
+  uint64_t padding : Padding<sizeof(uintptr_t)>::Value;
+
+  template <typename XType,
+            cpp::EnableIfType<cpp::IsSame<long double, XType>::Value, int> = 0>
+  explicit FPBits<long double>(XType x) {
+    *this = *reinterpret_cast<FPBits<long double> *>(&x);
+  }
+
+  operator long double() { return *reinterpret_cast<long double *>(this); }
+
+  int getExponent() const {
+    if (exponent == 0)
+      return int(1) - exponentBias;
+    return int(exponent) - exponentBias;
+  }
+
+  bool isZero() const {
+    return exponent == 0 && mantissa == 0 && implicitBit == 0;
+  }
+
+  bool isInf() const {
+    return exponent == maxExponent && mantissa == 0 && implicitBit == 1;
+  }
+
+  bool isNaN() const { return exponent == maxExponent && mantissa != 0; }
+
+  bool isInfOrNaN() const { return exponent == maxExponent; }
+
+  // Methods below this are used by tests.
+
+  template <typename XType,
+            cpp::EnableIfType<cpp::IsSame<UIntType, XType>::Value, int> = 0>
+  explicit FPBits<long double>(XType x) {
+    // The last 4 bytes of v are ignored in case of i386.
+    *this = *reinterpret_cast<FPBits<long double> *>(&x);
+  }
+
+  UIntType bitsAsUInt() const {
+    // We cannot just return the bits as is as it will lead to reading
+    // out of bounds in case of i386. So, we first copy the wider value
+    // before returning the value. This makes the last 4 bytes are always
+    // zero in case i386.
+    UIntType result = UIntType(0);
+    *reinterpret_cast<FPBits<long double> *>(&result) = *this;
+    return result;
+  }
+
+  static FPBits<long double> zero() { return FPBits<long double>(0.0l); }
+
+  static FPBits<long double> negZero() {
+    FPBits<long double> bits(0.0l);
+    bits.sign = 1;
+    return bits;
+  }
+
+  static FPBits<long double> inf() {
+    FPBits<long double> bits(0.0l);
+    bits.exponent = maxExponent;
+    bits.implicitBit = 1;
+    return bits;
+  }
+
+  static FPBits<long double> negInf() {
+    FPBits<long double> bits(0.0l);
+    bits.exponent = maxExponent;
+    bits.implicitBit = 1;
+    bits.sign = 1;
+    return bits;
+  }
+
+  static long double buildNaN(UIntType v) {
+    FPBits<long double> bits(0.0l);
+    bits.exponent = maxExponent;
+    bits.implicitBit = 1;
+    bits.mantissa = v;
+    return bits;
+  }
+};
+
+static_assert(
+    sizeof(FPBits<long double>) == sizeof(long double),
+    "Internal long double representation does not match the machine format.");
+
+} // namespace fputil
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_UTILS_FPUTIL_LONG_DOUBLE_BITS_X86_H
diff --git a/libc/utils/FPUtil/NearestIntegerOperations.h b/libc/utils/FPUtil/NearestIntegerOperations.h
index 7f93de6701126e..c0535f5993654b 100644
--- a/libc/utils/FPUtil/NearestIntegerOperations.h
+++ b/libc/utils/FPUtil/NearestIntegerOperations.h
@@ -10,6 +10,7 @@
 #define LLVM_LIBC_UTILS_FPUTIL_NEAREST_INTEGER_OPERATIONS_H
 
 #include "ClassificationFunctions.h"
+#include "FPBits.h"
 #include "FloatOperations.h"
 #include "FloatProperties.h"
 
@@ -21,32 +22,33 @@ namespace fputil {
 template <typename T,
           cpp::EnableIfType<cpp::IsFloatingPointType<T>::Value, int> = 0>
 static inline T trunc(T x) {
-  using Properties = FloatProperties<T>;
-  using BitsType = typename FloatProperties<T>::BitsType;
+  FPBits<T> bits(x);
 
-  BitsType bits = valueAsBits(x);
-
-  // If x is infinity, NaN or zero, return it.
-  if (bitsAreInfOrNaN(bits) || bitsAreZero(bits))
+  // If x is infinity or NaN, return it.
+  // If it is zero also we should return it as is, but the logic
+  // later in this function takes care of it. But not doing a zero
+  // check, we improve the run time of non-zero values.
+  if (bits.isInfOrNaN())
     return x;
 
-  int exponent = getExponentFromBits(bits);
+  int exponent = bits.getExponent();
 
   // If the exponent is greater than the most negative mantissa
   // exponent, then x is already an integer.
-  if (exponent >= static_cast<int>(Properties::mantissaWidth))
+  if (exponent >= static_cast<int>(MantissaWidth<T>::value))
     return x;
 
   // If the exponent is such that abs(x) is less than 1, then return 0.
   if (exponent <= -1) {
-    if (Properties::signMask & bits)
+    if (bits.sign)
       return T(-0.0);
     else
       return T(0.0);
   }
 
-  uint32_t trimSize = Properties::mantissaWidth - exponent;
-  return valueFromBits((bits >> trimSize) << trimSize);
+  int trimSize = MantissaWidth<T>::value - exponent;
+  bits.mantissa = (bits.mantissa >> trimSize) << trimSize;
+  return bits;
 }
 
 template <typename T,
diff --git a/libc/utils/MPFRWrapper/MPFRUtils.cpp b/libc/utils/MPFRWrapper/MPFRUtils.cpp
index 1bbc84d554c0e2..c6020f471e88d8 100644
--- a/libc/utils/MPFRWrapper/MPFRUtils.cpp
+++ b/libc/utils/MPFRWrapper/MPFRUtils.cpp
@@ -8,7 +8,7 @@
 
 #include "MPFRUtils.h"
 
-#include "utils/FPUtil/FloatOperations.h"
+#include "utils/FPUtil/FPBits.h"
 
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringRef.h"
@@ -17,14 +17,16 @@
 #include <stdint.h>
 #include <string>
 
+template <typename T> using FPBits = __llvm_libc::fputil::FPBits<T>;
+
 namespace __llvm_libc {
 namespace testing {
 namespace mpfr {
 
 class MPFRNumber {
   // A precision value which allows sufficiently large additional
-  // precision even compared to double precision floating point values.
-  static constexpr unsigned int mpfrPrecision = 96;
+  // precision even compared to quad-precision floating point values.
+  static constexpr unsigned int mpfrPrecision = 128;
 
   mpfr_t value;
 
@@ -48,6 +50,13 @@ class MPFRNumber {
     mpfr_set_d(value, x, MPFR_RNDN);
   }
 
+  template <typename XType,
+            cpp::EnableIfType<cpp::IsSame<long double, XType>::Value, int> = 0>
+  explicit MPFRNumber(XType x) {
+    mpfr_init2(value, mpfrPrecision);
+    mpfr_set_ld(value, x, MPFR_RNDN);
+  }
+
   template <typename XType,
             cpp::EnableIfType<cpp::IsIntegral<XType>::Value, int> = 0>
   explicit MPFRNumber(XType x) {
@@ -58,7 +67,7 @@ class MPFRNumber {
   template <typename XType> MPFRNumber(XType x, const Tolerance &t) {
     mpfr_init2(value, mpfrPrecision);
     mpfr_set_zero(value, 1); // Set to positive zero.
-    MPFRNumber xExponent(fputil::getExponent(x));
+    MPFRNumber xExponent(fputil::FPBits<XType>(x).getExponent());
     // E = 2^E
     mpfr_exp2(xExponent.value, xExponent.value, MPFR_RNDN);
     uint32_t bitMask = 1 << (t.width - 1);
@@ -155,24 +164,28 @@ namespace internal {
 
 template <typename T>
 void MPFRMatcher<T>::explainError(testutils::StreamWrapper &OS) {
-  using fputil::valueAsBits;
-
   MPFRNumber mpfrResult(operation, input);
   MPFRNumber mpfrInput(input);
   MPFRNumber mpfrMatchValue(matchValue);
   MPFRNumber mpfrToleranceValue(matchValue, tolerance);
+  FPBits<T> inputBits(input);
+  FPBits<T> matchBits(matchValue);
+  // TODO: Call to llvm::utohexstr implicitly converts __uint128_t values to
+  // uint64_t values. This can be fixed using a custom wrapper for
+  // llvm::utohexstr to handle __uint128_t values correctly.
   OS << "Match value not within tolerance value of MPFR result:\n"
      << "  Input decimal: " << mpfrInput.str() << '\n'
-     << "     Input bits: 0x" << llvm::utohexstr(valueAsBits(input)) << '\n'
+     << "     Input bits: 0x" << llvm::utohexstr(inputBits.bitsAsUInt()) << '\n'
      << "  Match decimal: " << mpfrMatchValue.str() << '\n'
-     << "     Match bits: 0x" << llvm::utohexstr(valueAsBits(matchValue))
-     << '\n'
+     << "     Match bits: 0x" << llvm::utohexstr(matchBits.bitsAsUInt()) << '\n'
      << "    MPFR result: " << mpfrResult.str() << '\n'
      << "Tolerance value: " << mpfrToleranceValue.str() << '\n';
 }
 
 template void MPFRMatcher<float>::explainError(testutils::StreamWrapper &);
 template void MPFRMatcher<double>::explainError(testutils::StreamWrapper &);
+template void
+MPFRMatcher<long double>::explainError(testutils::StreamWrapper &);
 
 template <typename T>
 bool compare(Operation op, T input, T libcResult, const Tolerance &t) {
@@ -185,6 +198,8 @@ bool compare(Operation op, T input, T libcResult, const Tolerance &t) {
 
 template bool compare<float>(Operation, float, float, const Tolerance &);
 template bool compare<double>(Operation, double, double, const Tolerance &);
+template bool compare<long double>(Operation, long double, long double,
+                                   const Tolerance &);
 
 } // namespace internal