diff --git a/libc/test/src/math/differential_testing/CMakeLists.txt b/libc/test/src/math/differential_testing/CMakeLists.txt
@@ -252,6 +252,17 @@ add_diff_binary(
     -fno-builtin
 )
 
+add_diff_binary(
+  log1pf_perf
+  SRCS
+    log1pf_perf.cpp
+  DEPENDS
+    .single_input_single_output_diff
+    libc.src.math.log1pf
+  COMPILE_OPTIONS
+    -fno-builtin
+)
+
 add_diff_binary(
   log2f_diff
   SRCS

diff --git a/libc/test/src/math/differential_testing/log1pf_perf.cpp b/libc/test/src/math/differential_testing/log1pf_perf.cpp
@@ -0,0 +1,16 @@
+//===-- Differential test for log1pf --------------------------------------===//
+//
+// 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 "SingleInputSingleOutputDiff.h"
+
+#include "src/math/log1pf.h"
+
+#include <math.h>
+
+SINGLE_INPUT_SINGLE_OUTPUT_PERF(float, __llvm_libc::log1pf, ::log1pf,
+                                "log1pf_perf.log")
diff --git a/libc/test/src/math/exhaustive/CMakeLists.txt b/libc/test/src/math/exhaustive/CMakeLists.txt
@@ -96,6 +96,23 @@ add_fp_unittest(
     -lpthread
 )
 
+add_fp_unittest(
+  log1pf_test
+  NO_RUN_POSTBUILD
+  NEED_MPFR
+  SUITE
+    libc_math_exhaustive_tests
+  SRCS
+    log1pf_test.cpp
+  DEPENDS
+    .exhaustive_test
+    libc.include.math
+    libc.src.math.log1pf
+    libc.src.__support.FPUtil.fputil
+  LINK_OPTIONS
+    -lpthread
+)
+
 add_fp_unittest(
   log2f_test
   NO_RUN_POSTBUILD

diff --git a/libc/test/src/math/exhaustive/log1pf_test.cpp b/libc/test/src/math/exhaustive/log1pf_test.cpp
@@ -0,0 +1,55 @@
+//===-- Exhaustive test for log1pf ----------------------------------------===//
+//
+// 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 "exhaustive_test.h"
+#include "src/__support/FPUtil/FPBits.h"
+#include "src/math/log1pf.h"
+#include "utils/MPFRWrapper/MPFRUtils.h"
+#include "utils/UnitTest/FPMatcher.h"
+
+using FPBits = __llvm_libc::fputil::FPBits<float>;
+
+namespace mpfr = __llvm_libc::testing::mpfr;
+
+struct LlvmLibclog1pfExhaustiveTest : public LlvmLibcExhaustiveTest<uint32_t> {
+  void check(uint32_t start, uint32_t stop,
+             mpfr::RoundingMode rounding) override {
+    mpfr::ForceRoundingMode r(rounding);
+    uint32_t bits = start;
+    do {
+      FPBits xbits(bits);
+      float x = float(xbits);
+      EXPECT_MPFR_MATCH(mpfr::Operation::Log1p, x, __llvm_libc::log1pf(x), 0.5,
+                        rounding);
+    } while (bits++ < stop);
+  }
+};
+
+// Range: All non-negative;
+static constexpr uint32_t START = 0x0000'0000U;
+static constexpr uint32_t STOP = 0x7f80'0000U;
+// Range: [-1, 0];
+// static constexpr uint32_t START = 0x8000'0000U;
+// static constexpr uint32_t STOP  = 0xbf80'0000U;
+static constexpr int NUM_THREADS = 16;
+
+TEST_F(LlvmLibclog1pfExhaustiveTest, RoundNearestTieToEven) {
+  test_full_range(START, STOP, NUM_THREADS, mpfr::RoundingMode::Nearest);
+}
+
+TEST_F(LlvmLibclog1pfExhaustiveTest, RoundUp) {
+  test_full_range(START, STOP, NUM_THREADS, mpfr::RoundingMode::Upward);
+}
+
+TEST_F(LlvmLibclog1pfExhaustiveTest, RoundDown) {
+  test_full_range(START, STOP, NUM_THREADS, mpfr::RoundingMode::Downward);
+}
+
+TEST_F(LlvmLibclog1pfExhaustiveTest, RoundTowardZero) {
+  test_full_range(START, STOP, NUM_THREADS, mpfr::RoundingMode::TowardZero);
+}
diff --git a/libc/test/src/math/log1pf_test.cpp b/libc/test/src/math/log1pf_test.cpp
@@ -0,0 +1,81 @@
+//===-- Unittests for log1pf ----------------------------------------------===//
+//
+// 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/FPUtil/FPBits.h"
+#include "src/math/log1pf.h"
+#include "utils/MPFRWrapper/MPFRUtils.h"
+#include "utils/UnitTest/FPMatcher.h"
+#include "utils/UnitTest/Test.h"
+#include <math.h>
+
+#include <errno.h>
+#include <stdint.h>
+
+namespace mpfr = __llvm_libc::testing::mpfr;
+
+DECLARE_SPECIAL_CONSTANTS(float)
+
+TEST(LlvmLibclog1pfTest, SpecialNumbers) {
+  EXPECT_FP_EQ(aNaN, __llvm_libc::log1pf(aNaN));
+  EXPECT_FP_EQ(inf, __llvm_libc::log1pf(inf));
+  EXPECT_TRUE(FPBits((__llvm_libc::log1pf(neg_inf))).is_nan());
+  EXPECT_FP_EQ(zero, __llvm_libc::log1pf(0.0f));
+  EXPECT_FP_EQ(neg_zero, __llvm_libc::log1pf(-0.0f));
+  EXPECT_FP_EQ(neg_inf, __llvm_libc::log1pf(-1.0f));
+}
+
+TEST(LlvmLibclog1pfTest, TrickyInputs) {
+  constexpr int N = 20;
+  constexpr uint32_t INPUTS[N] = {
+      0x35c00006U, /*0x1.80000cp-20f*/
+      0x35400003U, /*0x1.800006p-21f*/
+      0x3640000cU, /*0x1.800018p-19f*/
+      0x36c00018U, /*0x1.80003p-18f*/
+      0x3710001bU, /*0x1.200036p-17f*/
+      0x37400030U, /*0x1.80006p-17f*/
+      0x3770004bU, /*0x1.e00096p-17f*/
+      0x3b9315c8U, /*0x1.262b9p-8f*/
+      0x3c6eb7afU, /*0x1.dd6f5ep-7f*/
+      0x41078febU, /*0x1.0f1fd6p+3f*/
+      0x5cd69e88U, /*0x1.ad3d1p+58f*/
+      0x65d890d3U, /*0x1.b121a6p+76f*/
+      0x6f31a8ecU, /*0x1.6351d8p+95f*/
+      0x7a17f30aU, /*0x1.2fe614p+117f*/
+      0xb53ffffdU, /*-0x1.7ffffap-21f*/
+      0xb70fffe5U, /*-0x1.1fffcap-17f*/
+      0xbb0ec8c4U, /*-0x1.1d9188p-9f*/
+      0xbc4d092cU, /*-0x1.9a1258p-7f*/
+      0xbc657728U, /*-0x1.caee5p-7f*/
+      0xbd1d20afU, /*-0x1.3a415ep-5f*/
+  };
+  for (int i = 0; i < N; ++i) {
+    float x = float(FPBits(INPUTS[i]));
+    EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Log1p, x,
+                                   __llvm_libc::log1pf(x), 0.5);
+  }
+}
+
+TEST(LlvmLibclog1pfTest, InFloatRange) {
+  constexpr uint32_t COUNT = 1000000;
+  constexpr uint32_t STEP = UINT32_MAX / COUNT;
+  for (uint32_t i = 0, v = 0; i <= COUNT; ++i, v += STEP) {
+    float x = float(FPBits(v));
+    if (isnan(x) || isinf(x))
+      continue;
+    errno = 0;
+    float result = __llvm_libc::log1pf(x);
+    // If the computation resulted in an error or did not produce valid result
+    // in the single-precision floating point range, then ignore comparing with
+    // MPFR result as MPFR can still produce valid results because of its
+    // wider precision.
+    if (isnan(result) || isinf(result) || errno != 0)
+      continue;
+    ASSERT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Log1p, x,
+                                   __llvm_libc::log1pf(x), 0.5);
+  }
+}
diff --git a/libc/utils/MPFRWrapper/MPFRUtils.cpp b/libc/utils/MPFRWrapper/MPFRUtils.cpp
@@ -279,6 +279,12 @@ class MPFRNumber {
     return result;
   }
 
+  MPFRNumber log1p() const {
+    MPFRNumber result(*this);
+    mpfr_log1p(result.value, value, mpfr_rounding);
+    return result;
+  }
+
   MPFRNumber remquo(const MPFRNumber &divisor, int &quotient) {
     MPFRNumber remainder(*this);
     long q;
@@ -510,6 +516,8 @@ unary_operation(Operation op, InputType input, unsigned int precision,
     return mpfrInput.log2();
   case Operation::Log10:
     return mpfrInput.log10();
+  case Operation::Log1p:
+    return mpfrInput.log1p();
   case Operation::Mod2PI:
     return mpfrInput.mod_2pi();
   case Operation::ModPIOver2:

diff --git a/libc/utils/MPFRWrapper/MPFRUtils.h b/libc/utils/MPFRWrapper/MPFRUtils.h
@@ -33,6 +33,7 @@ enum class Operation : int {
   Log,
   Log2,
   Log10,
+  Log1p,
   Mod2PI,
   ModPIOver2,
   ModPIOver4,
-Original file line number
+Diff line change
@@ Expand Up / @@ -33,6 +33,7 @@ enum class Operation : int { @@
       Log,
       Log2,
       Log10,
+      Log1p,
       Mod2PI,
       ModPIOver2,
       ModPIOver4,
@@ Expand Down @@