[libc-commits] [libc] [libc] sqrt and log functions fuzz tests (PR #148006)

via libc-commits libc-commits at lists.llvm.org
Tue Jul 15 11:15:13 PDT 2025


https://github.com/sribee8 updated https://github.com/llvm/llvm-project/pull/148006

>From 129f09fe72e83cfc371c8586979b31c885e7c229 Mon Sep 17 00:00:00 2001
From: Sriya Pratipati <sriyap at google.com>
Date: Thu, 10 Jul 2025 17:12:06 +0000
Subject: [PATCH 1/6] [libc] sqrt and log functions fuzz tests

added fuzz tests for sqrt and log functions
---
 libc/fuzzing/math/CMakeLists.txt  | 45 +++++++++++++++++++++++++++++++
 libc/fuzzing/math/log10_fuzz.cpp  | 38 ++++++++++++++++++++++++++
 libc/fuzzing/math/log1p_fuzz.cpp  | 38 ++++++++++++++++++++++++++
 libc/fuzzing/math/log2_fuzz.cpp   | 38 ++++++++++++++++++++++++++
 libc/fuzzing/math/log_fuzz.cpp    | 38 ++++++++++++++++++++++++++
 libc/fuzzing/math/sincos_fuzz.cpp |  2 +-
 libc/fuzzing/math/sqrt_fuzz.cpp   | 38 ++++++++++++++++++++++++++
 7 files changed, 236 insertions(+), 1 deletion(-)
 create mode 100644 libc/fuzzing/math/log10_fuzz.cpp
 create mode 100644 libc/fuzzing/math/log1p_fuzz.cpp
 create mode 100644 libc/fuzzing/math/log2_fuzz.cpp
 create mode 100644 libc/fuzzing/math/log_fuzz.cpp
 create mode 100644 libc/fuzzing/math/sqrt_fuzz.cpp

diff --git a/libc/fuzzing/math/CMakeLists.txt b/libc/fuzzing/math/CMakeLists.txt
index e3c29651917fc..06f8f024762b9 100644
--- a/libc/fuzzing/math/CMakeLists.txt
+++ b/libc/fuzzing/math/CMakeLists.txt
@@ -124,3 +124,48 @@ add_libc_fuzzer(
   DEPENDS
     libc.src.math.sincos
 )
+
+add_libc_fuzzer(
+  log_fuzz
+  NEED_MPFR
+  SRCS
+    log_fuzz.cpp
+  DEPENDS
+    libc.src.math.log
+)
+
+add_libc_fuzzer(
+  log10_fuzz
+  NEED_MPFR
+  SRCS
+    log10_fuzz.cpp
+  DEPENDS
+    libc.src.math.log10
+)
+
+add_libc_fuzzer(
+  log1p_fuzz
+  NEED_MPFR
+  SRCS
+    log1p_fuzz.cpp
+  DEPENDS
+    libc.src.math.log1p
+)
+
+add_libc_fuzzer(
+  log2_fuzz
+  NEED_MPFR
+  SRCS
+    log2_fuzz.cpp
+  DEPENDS
+    libc.src.math.log2
+)
+
+add_libc_fuzzer(
+  sqrt_fuzz
+  NEED_MPFR
+  SRCS
+    sqrt_fuzz.cpp
+  DEPENDS
+    libc.src.math.sqrt
+)
diff --git a/libc/fuzzing/math/log10_fuzz.cpp b/libc/fuzzing/math/log10_fuzz.cpp
new file mode 100644
index 0000000000000..b5233588e83f8
--- /dev/null
+++ b/libc/fuzzing/math/log10_fuzz.cpp
@@ -0,0 +1,38 @@
+//===-- log10_fuzz.cpp ----------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// Fuzzing test for llvm-libc log10 implementation.
+///
+//===----------------------------------------------------------------------===//
+
+#include "src/math/log10.h"
+#include "utils/MPFRWrapper/mpfr_inc.h"
+#include <math.h>
+
+extern "C" int LLVMFuzzerTestOneInput(double x) {
+  // remove NaN and inf and values outside accepted range
+  if (isnan(x) || isinf(x) || x < 0)
+    return 0;
+  // signed zeros already tested in unit tests
+  if (signbit(x) && x == 0.0)
+    return 0;
+  mpfr_t input;
+  mpfr_init2(input, 53);
+  mpfr_set_d(input, x, MPFR_RNDN);
+  int output = mpfr_log10(input, input, MPFR_RNDN);
+  mpfr_subnormalize(input, output, MPFR_RNDN);
+  double to_compare = mpfr_get_d(input, MPFR_RNDN);
+
+  double result = LIBC_NAMESPACE::log10(x);
+
+  if (result != to_compare)
+    __builtin_trap();
+
+  mpfr_clear(input);
+  return 0;
+}
diff --git a/libc/fuzzing/math/log1p_fuzz.cpp b/libc/fuzzing/math/log1p_fuzz.cpp
new file mode 100644
index 0000000000000..c40aad018794f
--- /dev/null
+++ b/libc/fuzzing/math/log1p_fuzz.cpp
@@ -0,0 +1,38 @@
+//===-- log1p_fuzz.cpp ----------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// Fuzzing test for llvm-libc log1p implementation.
+///
+//===----------------------------------------------------------------------===//
+
+#include "src/math/log1p.h"
+#include "utils/MPFRWrapper/mpfr_inc.h"
+#include <math.h>
+
+extern "C" int LLVMFuzzerTestOneInput(double x) {
+  // remove NaN and inf and values outside accepted range
+  if (isnan(x) || isinf(x) || x < 0)
+    return 0;
+  // signed zeros already tested in unit tests
+  if (signbit(x) && x == 0.0)
+    return 0;
+  mpfr_t input;
+  mpfr_init2(input, 53);
+  mpfr_set_d(input, x, MPFR_RNDN);
+  int output = mpfr_log1p(input, input, MPFR_RNDN);
+  mpfr_subnormalize(input, output, MPFR_RNDN);
+  double to_compare = mpfr_get_d(input, MPFR_RNDN);
+
+  double result = LIBC_NAMESPACE::log1p(x);
+
+  if (result != to_compare)
+    __builtin_trap();
+
+  mpfr_clear(input);
+  return 0;
+}
diff --git a/libc/fuzzing/math/log2_fuzz.cpp b/libc/fuzzing/math/log2_fuzz.cpp
new file mode 100644
index 0000000000000..3a7d9956b4bea
--- /dev/null
+++ b/libc/fuzzing/math/log2_fuzz.cpp
@@ -0,0 +1,38 @@
+//===-- log2_fuzz.cpp -----------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// Fuzzing test for llvm-libc log2 implementation.
+///
+//===----------------------------------------------------------------------===//
+
+#include "src/math/log2.h"
+#include "utils/MPFRWrapper/mpfr_inc.h"
+#include <math.h>
+
+extern "C" int LLVMFuzzerTestOneInput(double x) {
+  // remove NaN and inf and values outside accepted range
+  if (isnan(x) || isinf(x) || x < 0)
+    return 0;
+  // signed zeros already tested in unit tests
+  if (signbit(x) && x == 0.0)
+    return 0;
+  mpfr_t input;
+  mpfr_init2(input, 53);
+  mpfr_set_d(input, x, MPFR_RNDN);
+  int output = mpfr_log2(input, input, MPFR_RNDN);
+  mpfr_subnormalize(input, output, MPFR_RNDN);
+  double to_compare = mpfr_get_d(input, MPFR_RNDN);
+
+  double result = LIBC_NAMESPACE::log2(x);
+
+  if (result != to_compare)
+    __builtin_trap();
+
+  mpfr_clear(input);
+  return 0;
+}
diff --git a/libc/fuzzing/math/log_fuzz.cpp b/libc/fuzzing/math/log_fuzz.cpp
new file mode 100644
index 0000000000000..1271fb73fd1a0
--- /dev/null
+++ b/libc/fuzzing/math/log_fuzz.cpp
@@ -0,0 +1,38 @@
+//===-- log_fuzz.cpp ------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// Fuzzing test for llvm-libc log implementation.
+///
+//===----------------------------------------------------------------------===//
+
+#include "src/math/log.h"
+#include "utils/MPFRWrapper/mpfr_inc.h"
+#include <math.h>
+
+extern "C" int LLVMFuzzerTestOneInput(double x) {
+  // remove NaN and inf and values outside accepted range
+  if (isnan(x) || isinf(x) || x < 0)
+    return 0;
+  // signed zeros already tested in unit tests
+  if (signbit(x) && x == 0.0)
+    return 0;
+  mpfr_t input;
+  mpfr_init2(input, 53);
+  mpfr_set_d(input, x, MPFR_RNDN);
+  int output = mpfr_log(input, input, MPFR_RNDN);
+  mpfr_subnormalize(input, output, MPFR_RNDN);
+  double to_compare = mpfr_get_d(input, MPFR_RNDN);
+
+  double result = LIBC_NAMESPACE::log(x);
+
+  if (result != to_compare)
+    __builtin_trap();
+
+  mpfr_clear(input);
+  return 0;
+}
diff --git a/libc/fuzzing/math/sincos_fuzz.cpp b/libc/fuzzing/math/sincos_fuzz.cpp
index 8cc6f7291a3df..fd3dfae23168c 100644
--- a/libc/fuzzing/math/sincos_fuzz.cpp
+++ b/libc/fuzzing/math/sincos_fuzz.cpp
@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 ///
-/// Fuzzing test for llvm-libc cos implementation.
+/// Fuzzing test for llvm-libc sincos implementation.
 ///
 //===----------------------------------------------------------------------===//
 
diff --git a/libc/fuzzing/math/sqrt_fuzz.cpp b/libc/fuzzing/math/sqrt_fuzz.cpp
new file mode 100644
index 0000000000000..48e17f481a256
--- /dev/null
+++ b/libc/fuzzing/math/sqrt_fuzz.cpp
@@ -0,0 +1,38 @@
+//===-- sqrt_fuzz.cpp -----------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// Fuzzing test for llvm-libc sqrt implementation.
+///
+//===----------------------------------------------------------------------===//
+
+#include "src/math/sqrt.h"
+#include "utils/MPFRWrapper/mpfr_inc.h"
+#include <math.h>
+
+extern "C" int LLVMFuzzerTestOneInput(double x) {
+  // remove NaN and inf and values outside accepted range
+  if (isnan(x) || isinf(x) || x < 0)
+    return 0;
+  // signed zeros already tested in unit tests
+  if (signbit(x) && x == 0.0)
+    return 0;
+  mpfr_t input;
+  mpfr_init2(input, 53);
+  mpfr_set_d(input, x, MPFR_RNDN);
+  int output = mpfr_sqrt(input, input, MPFR_RNDN);
+  mpfr_subnormalize(input, output, MPFR_RNDN);
+  double to_compare = mpfr_get_d(input, MPFR_RNDN);
+
+  double result = LIBC_NAMESPACE::sqrt(x);
+
+  if (result != to_compare)
+    __builtin_trap();
+
+  mpfr_clear(input);
+  return 0;
+}

>From d05a5baedfee2faf890dbb98451c9113136c7ce3 Mon Sep 17 00:00:00 2001
From: Sriya Pratipati <sriyap at google.com>
Date: Thu, 10 Jul 2025 21:20:29 +0000
Subject: [PATCH 2/6] changed to test internal sqrt

---
 libc/fuzzing/math/sqrt_fuzz.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libc/fuzzing/math/sqrt_fuzz.cpp b/libc/fuzzing/math/sqrt_fuzz.cpp
index 48e17f481a256..4f5f165a1e0f2 100644
--- a/libc/fuzzing/math/sqrt_fuzz.cpp
+++ b/libc/fuzzing/math/sqrt_fuzz.cpp
@@ -10,7 +10,7 @@
 ///
 //===----------------------------------------------------------------------===//
 
-#include "src/math/sqrt.h"
+#include "src/__support/FPUtil/generic/sqrt.h"
 #include "utils/MPFRWrapper/mpfr_inc.h"
 #include <math.h>
 
@@ -28,7 +28,7 @@ extern "C" int LLVMFuzzerTestOneInput(double x) {
   mpfr_subnormalize(input, output, MPFR_RNDN);
   double to_compare = mpfr_get_d(input, MPFR_RNDN);
 
-  double result = LIBC_NAMESPACE::sqrt(x);
+  double result = LIBC_NAMESPACE::fputil::sqrt<double>(x);
 
   if (result != to_compare)
     __builtin_trap();

>From 4db3dfe12e94a51effa3fd4697a66a6bc747e07d Mon Sep 17 00:00:00 2001
From: Sriya Pratipati <sriyap at google.com>
Date: Thu, 10 Jul 2025 21:26:38 +0000
Subject: [PATCH 3/6] updated cmake with correct dependancy

---
 libc/fuzzing/math/CMakeLists.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libc/fuzzing/math/CMakeLists.txt b/libc/fuzzing/math/CMakeLists.txt
index 06f8f024762b9..cbe4a278b6b70 100644
--- a/libc/fuzzing/math/CMakeLists.txt
+++ b/libc/fuzzing/math/CMakeLists.txt
@@ -167,5 +167,5 @@ add_libc_fuzzer(
   SRCS
     sqrt_fuzz.cpp
   DEPENDS
-    libc.src.math.sqrt
+    libc.src.__support.FPUtil.generic.sqrt
 )

>From b83fcf37484679faedc651bd564a0a85d313947e Mon Sep 17 00:00:00 2001
From: Sriya Pratipati <sriyap at google.com>
Date: Mon, 14 Jul 2025 16:35:45 +0000
Subject: [PATCH 4/6] updated condition

---
 libc/fuzzing/math/log1p_fuzz.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libc/fuzzing/math/log1p_fuzz.cpp b/libc/fuzzing/math/log1p_fuzz.cpp
index c40aad018794f..108baf5c6160c 100644
--- a/libc/fuzzing/math/log1p_fuzz.cpp
+++ b/libc/fuzzing/math/log1p_fuzz.cpp
@@ -16,7 +16,7 @@
 
 extern "C" int LLVMFuzzerTestOneInput(double x) {
   // remove NaN and inf and values outside accepted range
-  if (isnan(x) || isinf(x) || x < 0)
+  if (isnan(x) || isinf(x) || x < -1)
     return 0;
   // signed zeros already tested in unit tests
   if (signbit(x) && x == 0.0)

>From 5b5e4e6be3941904893360cc6844abe137fa3e8f Mon Sep 17 00:00:00 2001
From: Sriya Pratipati <sriyap at google.com>
Date: Tue, 15 Jul 2025 17:39:14 +0000
Subject: [PATCH 5/6] updated tests to correct format

---
 libc/fuzzing/math/CMakeLists.txt |  9 -------
 libc/fuzzing/math/atan_fuzz.cpp  | 38 ------------------------------
 libc/fuzzing/math/log10_fuzz.cpp | 39 ++++++++++++++++++++-----------
 libc/fuzzing/math/log1p_fuzz.cpp | 39 ++++++++++++++++++++-----------
 libc/fuzzing/math/log2_fuzz.cpp  | 39 ++++++++++++++++++++-----------
 libc/fuzzing/math/log_fuzz.cpp   | 40 ++++++++++++++++++++------------
 libc/fuzzing/math/sqrt_fuzz.cpp  | 39 ++++++++++++++++++++-----------
 7 files changed, 125 insertions(+), 118 deletions(-)
 delete mode 100644 libc/fuzzing/math/atan_fuzz.cpp

diff --git a/libc/fuzzing/math/CMakeLists.txt b/libc/fuzzing/math/CMakeLists.txt
index cbe4a278b6b70..4425fcd974455 100644
--- a/libc/fuzzing/math/CMakeLists.txt
+++ b/libc/fuzzing/math/CMakeLists.txt
@@ -98,15 +98,6 @@ add_libc_fuzzer(
     libc.src.math.cos
 )
 
-add_libc_fuzzer(
-  atan_fuzz
-  NEED_MPFR
-  SRCS
-    atan_fuzz.cpp
-  DEPENDS
-    libc.src.math.atan
-)
-
 add_libc_fuzzer(
   tan_fuzz
   NEED_MPFR
diff --git a/libc/fuzzing/math/atan_fuzz.cpp b/libc/fuzzing/math/atan_fuzz.cpp
deleted file mode 100644
index 3b485786e3a63..0000000000000
--- a/libc/fuzzing/math/atan_fuzz.cpp
+++ /dev/null
@@ -1,38 +0,0 @@
-//===-- atan_fuzz.cpp -----------------------------------------------------===//
-//
-// 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
-//
-//===----------------------------------------------------------------------===//
-///
-/// Fuzzing test for llvm-libc atan implementation.
-///
-//===----------------------------------------------------------------------===//
-
-#include "src/math/atan.h"
-#include "utils/MPFRWrapper/mpfr_inc.h"
-#include <math.h>
-
-extern "C" int LLVMFuzzerTestOneInput(double x) {
-  // remove NaN and inf
-  if (isnan(x) || isinf(x))
-    return 0;
-  // signed zeros already tested in unit tests
-  if (signbit(x) && x == 0.0)
-    return 0;
-  mpfr_t input;
-  mpfr_init2(input, 53);
-  mpfr_set_d(input, x, MPFR_RNDN);
-  int output = mpfr_atan(input, input, MPFR_RNDN);
-  mpfr_subnormalize(input, output, MPFR_RNDN);
-  double to_compare = mpfr_get_d(input, MPFR_RNDN);
-
-  double result = LIBC_NAMESPACE::atan(x);
-
-  if (result != to_compare)
-    __builtin_trap();
-
-  mpfr_clear(input);
-  return 0;
-}
diff --git a/libc/fuzzing/math/log10_fuzz.cpp b/libc/fuzzing/math/log10_fuzz.cpp
index b5233588e83f8..3254edc6d4a9b 100644
--- a/libc/fuzzing/math/log10_fuzz.cpp
+++ b/libc/fuzzing/math/log10_fuzz.cpp
@@ -12,27 +12,38 @@
 
 #include "src/math/log10.h"
 #include "utils/MPFRWrapper/mpfr_inc.h"
+#include <cstdint>
+#include <cstring>
+#include <iostream>
 #include <math.h>
 
-extern "C" int LLVMFuzzerTestOneInput(double x) {
-  // remove NaN and inf and values outside accepted range
-  if (isnan(x) || isinf(x) || x < 0)
-    return 0;
-  // signed zeros already tested in unit tests
-  if (signbit(x) && x == 0.0)
-    return 0;
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
   mpfr_t input;
   mpfr_init2(input, 53);
-  mpfr_set_d(input, x, MPFR_RNDN);
-  int output = mpfr_log10(input, input, MPFR_RNDN);
-  mpfr_subnormalize(input, output, MPFR_RNDN);
-  double to_compare = mpfr_get_d(input, MPFR_RNDN);
+  for (size_t i = 0; i < size / sizeof(double); ++i) {
+    double x;
+    std::memcpy(&x, data, sizeof(double));
+    // remove NaN and inf and values outside accepted range
+    if (isnan(x) || isinf(x) || x < 0)
+      return 0;
+    // signed zeros already tested in unit tests
+    if (signbit(x) && x == 0.0)
+      return 0;
 
-  double result = LIBC_NAMESPACE::log10(x);
+    mpfr_set_d(input, x, MPFR_RNDN);
+    int output = mpfr_log10(input, input, MPFR_RNDN);
+    mpfr_subnormalize(input, output, MPFR_RNDN);
+    double to_compare = mpfr_get_d(input, MPFR_RNDN);
 
-  if (result != to_compare)
-    __builtin_trap();
+    double result = LIBC_NAMESPACE::log10(x);
 
+    if (result != to_compare) {
+      std::cout << std::hexfloat << "Failing input: " << x << std::endl;
+      std::cout << std::hexfloat << "Failing output: " << result << std::endl;
+      std::cout << std::hexfloat << "Expected: " << to_compare << std::endl;
+      __builtin_trap();
+    }
+  }
   mpfr_clear(input);
   return 0;
 }
diff --git a/libc/fuzzing/math/log1p_fuzz.cpp b/libc/fuzzing/math/log1p_fuzz.cpp
index 108baf5c6160c..70186363b5a41 100644
--- a/libc/fuzzing/math/log1p_fuzz.cpp
+++ b/libc/fuzzing/math/log1p_fuzz.cpp
@@ -12,27 +12,38 @@
 
 #include "src/math/log1p.h"
 #include "utils/MPFRWrapper/mpfr_inc.h"
+#include <cstdint>
+#include <cstring>
+#include <iostream>
 #include <math.h>
 
-extern "C" int LLVMFuzzerTestOneInput(double x) {
-  // remove NaN and inf and values outside accepted range
-  if (isnan(x) || isinf(x) || x < -1)
-    return 0;
-  // signed zeros already tested in unit tests
-  if (signbit(x) && x == 0.0)
-    return 0;
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
   mpfr_t input;
   mpfr_init2(input, 53);
-  mpfr_set_d(input, x, MPFR_RNDN);
-  int output = mpfr_log1p(input, input, MPFR_RNDN);
-  mpfr_subnormalize(input, output, MPFR_RNDN);
-  double to_compare = mpfr_get_d(input, MPFR_RNDN);
+  for (size_t i = 0; i < size / sizeof(double); ++i) {
+    double x;
+    std::memcpy(&x, data, sizeof(double));
+    // remove NaN and inf and values outside accepted range
+    if (isnan(x) || isinf(x) || x < -1)
+      return 0;
+    // signed zeros already tested in unit tests
+    if (signbit(x) && x == 0.0)
+      return 0;
 
-  double result = LIBC_NAMESPACE::log1p(x);
+    mpfr_set_d(input, x, MPFR_RNDN);
+    int output = mpfr_log1p(input, input, MPFR_RNDN);
+    mpfr_subnormalize(input, output, MPFR_RNDN);
+    double to_compare = mpfr_get_d(input, MPFR_RNDN);
 
-  if (result != to_compare)
-    __builtin_trap();
+    double result = LIBC_NAMESPACE::log1p(x);
 
+    if (result != to_compare) {
+      std::cout << std::hexfloat << "Failing input: " << x << std::endl;
+      std::cout << std::hexfloat << "Failing output: " << result << std::endl;
+      std::cout << std::hexfloat << "Expected: " << to_compare << std::endl;
+      __builtin_trap();
+    }
+  }
   mpfr_clear(input);
   return 0;
 }
diff --git a/libc/fuzzing/math/log2_fuzz.cpp b/libc/fuzzing/math/log2_fuzz.cpp
index 3a7d9956b4bea..7bf77212c4d47 100644
--- a/libc/fuzzing/math/log2_fuzz.cpp
+++ b/libc/fuzzing/math/log2_fuzz.cpp
@@ -12,27 +12,38 @@
 
 #include "src/math/log2.h"
 #include "utils/MPFRWrapper/mpfr_inc.h"
+#include <cstdint>
+#include <cstring>
+#include <iostream>
 #include <math.h>
 
-extern "C" int LLVMFuzzerTestOneInput(double x) {
-  // remove NaN and inf and values outside accepted range
-  if (isnan(x) || isinf(x) || x < 0)
-    return 0;
-  // signed zeros already tested in unit tests
-  if (signbit(x) && x == 0.0)
-    return 0;
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
   mpfr_t input;
   mpfr_init2(input, 53);
-  mpfr_set_d(input, x, MPFR_RNDN);
-  int output = mpfr_log2(input, input, MPFR_RNDN);
-  mpfr_subnormalize(input, output, MPFR_RNDN);
-  double to_compare = mpfr_get_d(input, MPFR_RNDN);
+  for (size_t i = 0; i < size / sizeof(double); ++i) {
+    double x;
+    std::memcpy(&x, data, sizeof(double));
+    // remove NaN and inf and values outside accepted range
+    if (isnan(x) || isinf(x) || x < 0)
+      return 0;
+    // signed zeros already tested in unit tests
+    if (signbit(x) && x == 0.0)
+      return 0;
 
-  double result = LIBC_NAMESPACE::log2(x);
+    mpfr_set_d(input, x, MPFR_RNDN);
+    int output = mpfr_log2(input, input, MPFR_RNDN);
+    mpfr_subnormalize(input, output, MPFR_RNDN);
+    double to_compare = mpfr_get_d(input, MPFR_RNDN);
 
-  if (result != to_compare)
-    __builtin_trap();
+    double result = LIBC_NAMESPACE::log2(x);
 
+    if (result != to_compare) {
+      std::cout << std::hexfloat << "Failing input: " << x << std::endl;
+      std::cout << std::hexfloat << "Failing output: " << result << std::endl;
+      std::cout << std::hexfloat << "Expected: " << to_compare << std::endl;
+      __builtin_trap();
+    }
+  }
   mpfr_clear(input);
   return 0;
 }
diff --git a/libc/fuzzing/math/log_fuzz.cpp b/libc/fuzzing/math/log_fuzz.cpp
index 1271fb73fd1a0..4b84b2b72dd78 100644
--- a/libc/fuzzing/math/log_fuzz.cpp
+++ b/libc/fuzzing/math/log_fuzz.cpp
@@ -12,27 +12,37 @@
 
 #include "src/math/log.h"
 #include "utils/MPFRWrapper/mpfr_inc.h"
+#include <cstdint>
+#include <cstring>
+#include <iostream>
 #include <math.h>
 
-extern "C" int LLVMFuzzerTestOneInput(double x) {
-  // remove NaN and inf and values outside accepted range
-  if (isnan(x) || isinf(x) || x < 0)
-    return 0;
-  // signed zeros already tested in unit tests
-  if (signbit(x) && x == 0.0)
-    return 0;
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
   mpfr_t input;
   mpfr_init2(input, 53);
-  mpfr_set_d(input, x, MPFR_RNDN);
-  int output = mpfr_log(input, input, MPFR_RNDN);
-  mpfr_subnormalize(input, output, MPFR_RNDN);
-  double to_compare = mpfr_get_d(input, MPFR_RNDN);
+  for (size_t i = 0; i < size / sizeof(double); ++i) {
+    double x;
+    std::memcpy(&x, data, sizeof(double));
+    // remove NaN and inf and values outside accepted range
+    if (isnan(x) || isinf(x) || x < 0)
+      return 0;
+    // signed zeros already tested in unit tests
+    if (signbit(x) && x == 0.0)
+      return 0;
+    mpfr_set_d(input, x, MPFR_RNDN);
+    int output = mpfr_log(input, input, MPFR_RNDN);
+    mpfr_subnormalize(input, output, MPFR_RNDN);
+    double to_compare = mpfr_get_d(input, MPFR_RNDN);
 
-  double result = LIBC_NAMESPACE::log(x);
-
-  if (result != to_compare)
-    __builtin_trap();
+    double result = LIBC_NAMESPACE::log(x);
 
+    if (result != to_compare) {
+      std::cout << std::hexfloat << "Failing input: " << x << std::endl;
+      std::cout << std::hexfloat << "Failing output: " << result << std::endl;
+      std::cout << std::hexfloat << "Expected: " << to_compare << std::endl;
+      __builtin_trap();
+    }
+  }
   mpfr_clear(input);
   return 0;
 }
diff --git a/libc/fuzzing/math/sqrt_fuzz.cpp b/libc/fuzzing/math/sqrt_fuzz.cpp
index 4f5f165a1e0f2..447517a55d247 100644
--- a/libc/fuzzing/math/sqrt_fuzz.cpp
+++ b/libc/fuzzing/math/sqrt_fuzz.cpp
@@ -12,27 +12,38 @@
 
 #include "src/__support/FPUtil/generic/sqrt.h"
 #include "utils/MPFRWrapper/mpfr_inc.h"
+#include <cstdint>
+#include <cstring>
+#include <iostream>
 #include <math.h>
 
-extern "C" int LLVMFuzzerTestOneInput(double x) {
-  // remove NaN and inf and values outside accepted range
-  if (isnan(x) || isinf(x) || x < 0)
-    return 0;
-  // signed zeros already tested in unit tests
-  if (signbit(x) && x == 0.0)
-    return 0;
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
   mpfr_t input;
   mpfr_init2(input, 53);
-  mpfr_set_d(input, x, MPFR_RNDN);
-  int output = mpfr_sqrt(input, input, MPFR_RNDN);
-  mpfr_subnormalize(input, output, MPFR_RNDN);
-  double to_compare = mpfr_get_d(input, MPFR_RNDN);
+  for (size_t i = 0; i < size / sizeof(double); ++i) {
+    double x;
+    std::memcpy(&x, data, sizeof(double));
+    // remove NaN and inf and values outside accepted range
+    if (isnan(x) || isinf(x) || x < 0)
+      return 0;
+    // signed zeros already tested in unit tests
+    if (signbit(x) && x == 0.0)
+      return 0;
 
-  double result = LIBC_NAMESPACE::fputil::sqrt<double>(x);
+    mpfr_set_d(input, x, MPFR_RNDN);
+    int output = mpfr_sqrt(input, input, MPFR_RNDN);
+    mpfr_subnormalize(input, output, MPFR_RNDN);
+    double to_compare = mpfr_get_d(input, MPFR_RNDN);
 
-  if (result != to_compare)
-    __builtin_trap();
+    double result = LIBC_NAMESPACE::fputil::sqrt<double>(x);
 
+    if (result != to_compare) {
+      std::cout << std::hexfloat << "Failing input: " << x << std::endl;
+      std::cout << std::hexfloat << "Failing output: " << result << std::endl;
+      std::cout << std::hexfloat << "Expected: " << to_compare << std::endl;
+      __builtin_trap();
+    }
+  }
   mpfr_clear(input);
   return 0;
 }

>From c42124d9a674ea1dd19107ba1ff7a88213ed6189 Mon Sep 17 00:00:00 2001
From: Sriya Pratipati <sriyap at google.com>
Date: Tue, 15 Jul 2025 18:14:55 +0000
Subject: [PATCH 6/6] added incrementing the data pointer

---
 libc/fuzzing/math/log10_fuzz.cpp | 2 ++
 libc/fuzzing/math/log1p_fuzz.cpp | 1 +
 libc/fuzzing/math/log2_fuzz.cpp  | 2 ++
 libc/fuzzing/math/log_fuzz.cpp   | 2 ++
 libc/fuzzing/math/sqrt_fuzz.cpp  | 1 +
 5 files changed, 8 insertions(+)

diff --git a/libc/fuzzing/math/log10_fuzz.cpp b/libc/fuzzing/math/log10_fuzz.cpp
index 3254edc6d4a9b..23134f4903a45 100644
--- a/libc/fuzzing/math/log10_fuzz.cpp
+++ b/libc/fuzzing/math/log10_fuzz.cpp
@@ -23,6 +23,8 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
   for (size_t i = 0; i < size / sizeof(double); ++i) {
     double x;
     std::memcpy(&x, data, sizeof(double));
+    data += sizeof(double);
+
     // remove NaN and inf and values outside accepted range
     if (isnan(x) || isinf(x) || x < 0)
       return 0;
diff --git a/libc/fuzzing/math/log1p_fuzz.cpp b/libc/fuzzing/math/log1p_fuzz.cpp
index 70186363b5a41..5e138a65e3716 100644
--- a/libc/fuzzing/math/log1p_fuzz.cpp
+++ b/libc/fuzzing/math/log1p_fuzz.cpp
@@ -23,6 +23,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
   for (size_t i = 0; i < size / sizeof(double); ++i) {
     double x;
     std::memcpy(&x, data, sizeof(double));
+    data += sizeof(double);
     // remove NaN and inf and values outside accepted range
     if (isnan(x) || isinf(x) || x < -1)
       return 0;
diff --git a/libc/fuzzing/math/log2_fuzz.cpp b/libc/fuzzing/math/log2_fuzz.cpp
index 7bf77212c4d47..aa19649b95126 100644
--- a/libc/fuzzing/math/log2_fuzz.cpp
+++ b/libc/fuzzing/math/log2_fuzz.cpp
@@ -23,6 +23,8 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
   for (size_t i = 0; i < size / sizeof(double); ++i) {
     double x;
     std::memcpy(&x, data, sizeof(double));
+    data += sizeof(double);
+
     // remove NaN and inf and values outside accepted range
     if (isnan(x) || isinf(x) || x < 0)
       return 0;
diff --git a/libc/fuzzing/math/log_fuzz.cpp b/libc/fuzzing/math/log_fuzz.cpp
index 4b84b2b72dd78..03aa678d1f16c 100644
--- a/libc/fuzzing/math/log_fuzz.cpp
+++ b/libc/fuzzing/math/log_fuzz.cpp
@@ -23,6 +23,8 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
   for (size_t i = 0; i < size / sizeof(double); ++i) {
     double x;
     std::memcpy(&x, data, sizeof(double));
+    data += sizeof(double);
+
     // remove NaN and inf and values outside accepted range
     if (isnan(x) || isinf(x) || x < 0)
       return 0;
diff --git a/libc/fuzzing/math/sqrt_fuzz.cpp b/libc/fuzzing/math/sqrt_fuzz.cpp
index 447517a55d247..e81cf1afd3728 100644
--- a/libc/fuzzing/math/sqrt_fuzz.cpp
+++ b/libc/fuzzing/math/sqrt_fuzz.cpp
@@ -23,6 +23,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
   for (size_t i = 0; i < size / sizeof(double); ++i) {
     double x;
     std::memcpy(&x, data, sizeof(double));
+    data += sizeof(double);
     // remove NaN and inf and values outside accepted range
     if (isnan(x) || isinf(x) || x < 0)
       return 0;



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