[libc-commits] [libc] [llvm] [libc][math] Refactor log_bf16 to Header (PR #186618)
via libc-commits
libc-commits at lists.llvm.org
Sat Mar 14 13:03:32 PDT 2026
https://github.com/Sukumarsawant updated https://github.com/llvm/llvm-project/pull/186618
>From 124002501ad32a76a5ac0be0ac100f2a5acd0d2c Mon Sep 17 00:00:00 2001
From: Sukumarsawant <sawantsukumar at gmail.com>
Date: Sun, 15 Mar 2026 00:09:55 +0530
Subject: [PATCH 1/2] eat: refactor log_bf16
feat: refactor log_bf16
test
test
test
test
test
---
libc/shared/math.h | 1 +
libc/shared/math/log_bf16.h | 23 +++
libc/src/__support/math/CMakeLists.txt | 15 ++
libc/src/__support/math/log_bf16.h | 145 ++++++++++++++++++
libc/src/math/generic/CMakeLists.txt | 8 +-
libc/src/math/generic/log_bf16.cpp | 123 +--------------
libc/test/shared/CMakeLists.txt | 1 +
libc/test/shared/shared_math_test.cpp | 3 +
.../llvm-project-overlay/libc/BUILD.bazel | 22 +++
9 files changed, 213 insertions(+), 128 deletions(-)
create mode 100644 libc/shared/math/log_bf16.h
create mode 100644 libc/src/__support/math/log_bf16.h
diff --git a/libc/shared/math.h b/libc/shared/math.h
index 61c3ddffd74e5..8563f3a963729 100644
--- a/libc/shared/math.h
+++ b/libc/shared/math.h
@@ -180,6 +180,7 @@
#include "math/log2.h"
#include "math/log2f.h"
#include "math/log2f16.h"
+#include "math/log_bf16.h"
#include "math/logb.h"
#include "math/logbf.h"
#include "math/logbf128.h"
diff --git a/libc/shared/math/log_bf16.h b/libc/shared/math/log_bf16.h
new file mode 100644
index 0000000000000..d431133cfaa42
--- /dev/null
+++ b/libc/shared/math/log_bf16.h
@@ -0,0 +1,23 @@
+//===-- Shared log_bf16 function --------------------------------*- 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_SHARED_MATH_LOG_BF16_H
+#define LLVM_LIBC_SHARED_MATH_LOG_BF16_H
+
+#include "shared/libc_common.h"
+#include "src/__support/math/log_bf16.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace shared {
+
+using math::log_bf16;
+
+} // namespace shared
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SHARED_MATH_LOG_BF16_H
diff --git a/libc/src/__support/math/CMakeLists.txt b/libc/src/__support/math/CMakeLists.txt
index 8bb935d863a9b..1b9dd1880ffe4 100644
--- a/libc/src/__support/math/CMakeLists.txt
+++ b/libc/src/__support/math/CMakeLists.txt
@@ -2829,6 +2829,21 @@ add_header_library(
libc.src.__support.uint128
)
+add_header_library(
+ log_bf16
+ HDRS
+ log_bf16.h
+ DEPENDS
+ libc.src.__support.FPUtil.fp_bits
+ libc.src.__support.FPUtil.bfloat16
+ libc.src.__support.FPUtil.cast
+ libc.src.__support.FPUtil.multiply_add
+ libc.src.__support.common
+ libc.src.__support.macros.config
+ libc.src.__support.macros.optimization
+ libc.src.__support.macros.properties.cpu_features
+)
+
add_header_library(
pow
HDRS
diff --git a/libc/src/__support/math/log_bf16.h b/libc/src/__support/math/log_bf16.h
new file mode 100644
index 0000000000000..7575079770bb9
--- /dev/null
+++ b/libc/src/__support/math/log_bf16.h
@@ -0,0 +1,145 @@
+//===-- Implementation header for log_bf16 ----------------------*- 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___SUPPORT_MATH_LOG_BF16_H
+#define LLVM_LIBC_SRC___SUPPORT_MATH_LOG_BF16_H
+
+#include "src/__support/FPUtil/FPBits.h"
+#include "src/__support/FPUtil/bfloat16.h"
+#include "src/__support/FPUtil/cast.h"
+#include "src/__support/FPUtil/multiply_add.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/config.h"
+#include "src/__support/macros/optimization.h"
+#include "src/__support/macros/properties/cpu_features.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+namespace math {
+
+// Generated by Sollya with the following commands:
+// > display = hexadecimal;
+// > round(log(2), SG, RN);
+LIBC_INLINE_VAR constexpr float BF16_LOGF_2 = 0x1.62e43p-1f;
+
+// Generated by Sollya with the following commands:
+// > display = hexadecimal;
+// > for i from 0 to 127 do print(round(log(1 + i * 2^-7), SG, RN));
+LIBC_INLINE_VAR constexpr float LOG_1_PLUS_M[128] = {
+ 0x0.0p0f, 0x1.fe02a6p-8f, 0x1.fc0a8cp-7f, 0x1.7b91bp-6f,
+ 0x1.f829bp-6f, 0x1.39e87cp-5f, 0x1.77459p-5f, 0x1.b42dd8p-5f,
+ 0x1.f0a30cp-5f, 0x1.16536ep-4f, 0x1.341d7ap-4f, 0x1.51b074p-4f,
+ 0x1.6f0d28p-4f, 0x1.8c345ep-4f, 0x1.a926d4p-4f, 0x1.c5e548p-4f,
+ 0x1.e27076p-4f, 0x1.fec914p-4f, 0x1.0d77e8p-3f, 0x1.1b72aep-3f,
+ 0x1.29553p-3f, 0x1.371fc2p-3f, 0x1.44d2b6p-3f, 0x1.526e5ep-3f,
+ 0x1.5ff308p-3f, 0x1.6d60fep-3f, 0x1.7ab89p-3f, 0x1.87fa06p-3f,
+ 0x1.9525aap-3f, 0x1.a23bc2p-3f, 0x1.af3c94p-3f, 0x1.bc2868p-3f,
+ 0x1.c8ff7cp-3f, 0x1.d5c216p-3f, 0x1.e27076p-3f, 0x1.ef0adcp-3f,
+ 0x1.fb9186p-3f, 0x1.04025ap-2f, 0x1.0a324ep-2f, 0x1.1058cp-2f,
+ 0x1.1675cap-2f, 0x1.1c898cp-2f, 0x1.22942p-2f, 0x1.2895a2p-2f,
+ 0x1.2e8e2cp-2f, 0x1.347ddap-2f, 0x1.3a64c6p-2f, 0x1.404308p-2f,
+ 0x1.4618bcp-2f, 0x1.4be5fap-2f, 0x1.51aad8p-2f, 0x1.576772p-2f,
+ 0x1.5d1bdcp-2f, 0x1.62c83p-2f, 0x1.686c82p-2f, 0x1.6e08eap-2f,
+ 0x1.739d8p-2f, 0x1.792a56p-2f, 0x1.7eaf84p-2f, 0x1.842d1ep-2f,
+ 0x1.89a338p-2f, 0x1.8f11e8p-2f, 0x1.947942p-2f, 0x1.99d958p-2f,
+ 0x1.9f323ep-2f, 0x1.a4840ap-2f, 0x1.a9cecap-2f, 0x1.af1294p-2f,
+ 0x1.b44f78p-2f, 0x1.b9858ap-2f, 0x1.beb4dap-2f, 0x1.c3dd7ap-2f,
+ 0x1.c8ff7cp-2f, 0x1.ce1afp-2f, 0x1.d32fe8p-2f, 0x1.d83e72p-2f,
+ 0x1.dd46ap-2f, 0x1.e24882p-2f, 0x1.e74426p-2f, 0x1.ec399ep-2f,
+ 0x1.f128f6p-2f, 0x1.f6124p-2f, 0x1.faf588p-2f, 0x1.ffd2ep-2f,
+ 0x1.02552ap-1f, 0x1.04bdfap-1f, 0x1.0723e6p-1f, 0x1.0986f4p-1f,
+ 0x1.0be72ep-1f, 0x1.0e4498p-1f, 0x1.109f3ap-1f, 0x1.12f71ap-1f,
+ 0x1.154c3ep-1f, 0x1.179eacp-1f, 0x1.19ee6cp-1f, 0x1.1c3b82p-1f,
+ 0x1.1e85f6p-1f, 0x1.20cdcep-1f, 0x1.23130ep-1f, 0x1.2555bcp-1f,
+ 0x1.2795e2p-1f, 0x1.29d38p-1f, 0x1.2c0e9ep-1f, 0x1.2e4744p-1f,
+ 0x1.307d74p-1f, 0x1.32b134p-1f, 0x1.34e28ap-1f, 0x1.37117cp-1f,
+ 0x1.393e0ep-1f, 0x1.3b6844p-1f, 0x1.3d9026p-1f, 0x1.3fb5b8p-1f,
+ 0x1.41d8fep-1f, 0x1.43f9fep-1f, 0x1.4618bcp-1f, 0x1.48353ep-1f,
+ 0x1.4a4f86p-1f, 0x1.4c679ap-1f, 0x1.4e7d82p-1f, 0x1.50913cp-1f,
+ 0x1.52a2d2p-1f, 0x1.54b246p-1f, 0x1.56bf9ep-1f, 0x1.58cadcp-1f,
+ 0x1.5ad404p-1f, 0x1.5cdb1ep-1f, 0x1.5ee02ap-1f, 0x1.60e33p-1f,
+};
+
+LIBC_INLINE bfloat16 log_bf16(bfloat16 x) {
+ using FPBits = fputil::FPBits<bfloat16>;
+ FPBits x_bits(x);
+
+ uint16_t x_u = x_bits.uintval();
+
+ // If x <= 0, or x is 1, or x is +inf, or x is NaN.
+ if (LIBC_UNLIKELY(x_u == 0U || x_u == 0x3f80U || x_u >= 0x7f80U)) {
+ // log(NaN) = NaN
+ if (x_bits.is_nan()) {
+ if (x_bits.is_signaling_nan()) {
+ fputil::raise_except_if_required(FE_INVALID);
+ return FPBits::quiet_nan().get_val();
+ }
+
+ return x;
+ }
+
+ // log(+/-0) = −inf
+ if ((x_u & 0x7fffU) == 0U) {
+ fputil::raise_except_if_required(FE_DIVBYZERO);
+ return FPBits::inf(Sign::NEG).get_val();
+ }
+
+ // log(1) = 0
+ if (x_u == 0x3f80U)
+ return FPBits::zero().get_val();
+
+ // x < 0
+ if (x_u > 0x8000U) {
+ fputil::set_errno_if_required(EDOM);
+ fputil::raise_except_if_required(FE_INVALID);
+ return FPBits::quiet_nan().get_val();
+ }
+
+ // log(+inf) = +inf
+ return FPBits::inf().get_val();
+ }
+
+#ifndef LIBC_TARGET_CPU_HAS_FMA
+ // log(0.00000000000000171390679426508540927898138761520386)
+ // ~= -34.00000095
+ if (LIBC_UNLIKELY(x_u == 0x26F7U))
+ return bfloat16(-34.0000009);
+#endif // LIBC_TARGET_CPU_HAS_FMA
+
+ int e = -FPBits::EXP_BIAS;
+
+ // When x is subnormal, normalize it.
+ if ((x_u & FPBits::EXP_MASK) == 0U) {
+ // Can't pass an integer to fputil::cast directly.
+ constexpr float NORMALIZE_EXP = 1U << FPBits::FRACTION_LEN;
+ x_bits = FPBits(x_bits.get_val() * fputil::cast<bfloat16>(NORMALIZE_EXP));
+ x_u = x_bits.uintval();
+ e -= FPBits::FRACTION_LEN;
+ }
+
+ // To compute log(x), we perform the following range reduction:
+ // x = 2^e * (1 + m),
+ // log(x) = e * log(2) + log(1 + m).
+ // for BFloat16, mantissa is at most 7 explicit bits, so we lookup
+ // log(1 + m) in LOG_1_PLUS_M table using `m` as key.
+
+ // Get the 7-bit mantissa directly as the table index
+ uint16_t m = x_bits.get_mantissa();
+
+ // Get unbiased exponent
+ e += x_u >> FPBits::FRACTION_LEN;
+
+ return fputil::cast<bfloat16>(
+ fputil::multiply_add(static_cast<float>(e), BF16_LOGF_2, LOG_1_PLUS_M[m]));
+}
+
+} // namespace math
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC___SUPPORT_MATH_LOG_BF16_H
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index 07c48c9a04c98..f1f2f12d351c4 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -1947,13 +1947,7 @@ add_entrypoint_object(
HDRS
../log_bf16.h
DEPENDS
- libc.src.__support.common
- libc.src.__support.FPUtil.bfloat16
- libc.src.__support.FPUtil.cast
- libc.src.__support.FPUtil.fp_bits
- libc.src.__support.FPUtil.multiply_add
- libc.src.__support.macros.config
- libc.src.__support.macros.optimization
+ libc.src.__support.math.log_bf16
)
add_entrypoint_object(
diff --git a/libc/src/math/generic/log_bf16.cpp b/libc/src/math/generic/log_bf16.cpp
index 213dccca0fb9e..53a02320328b2 100644
--- a/libc/src/math/generic/log_bf16.cpp
+++ b/libc/src/math/generic/log_bf16.cpp
@@ -7,131 +7,12 @@
//===----------------------------------------------------------------------===//
#include "src/math/log_bf16.h"
-#include "src/__support/FPUtil/FPBits.h"
-#include "src/__support/FPUtil/bfloat16.h"
-#include "src/__support/FPUtil/cast.h"
-#include "src/__support/FPUtil/multiply_add.h"
-#include "src/__support/common.h"
-#include "src/__support/macros/config.h"
-#include "src/__support/macros/optimization.h"
-#include "src/__support/macros/properties/cpu_features.h"
+#include "src/__support/math/log_bf16.h"
namespace LIBC_NAMESPACE_DECL {
-// Generated by Sollya with the following commands:
-// > display = hexadecimal;
-// > round(log(2), SG, RN);
-static constexpr float LOGF_2 = 0x1.62e43p-1f;
-
-// Generated by Sollya with the following commands:
-// > display = hexadecimal;
-// > for i from 0 to 127 do print(round(log(1 + i * 2^-7), SG, RN));
-static constexpr float LOG_1_PLUS_M[128] = {
- 0x0.0p0f, 0x1.fe02a6p-8f, 0x1.fc0a8cp-7f, 0x1.7b91bp-6f,
- 0x1.f829bp-6f, 0x1.39e87cp-5f, 0x1.77459p-5f, 0x1.b42dd8p-5f,
- 0x1.f0a30cp-5f, 0x1.16536ep-4f, 0x1.341d7ap-4f, 0x1.51b074p-4f,
- 0x1.6f0d28p-4f, 0x1.8c345ep-4f, 0x1.a926d4p-4f, 0x1.c5e548p-4f,
- 0x1.e27076p-4f, 0x1.fec914p-4f, 0x1.0d77e8p-3f, 0x1.1b72aep-3f,
- 0x1.29553p-3f, 0x1.371fc2p-3f, 0x1.44d2b6p-3f, 0x1.526e5ep-3f,
- 0x1.5ff308p-3f, 0x1.6d60fep-3f, 0x1.7ab89p-3f, 0x1.87fa06p-3f,
- 0x1.9525aap-3f, 0x1.a23bc2p-3f, 0x1.af3c94p-3f, 0x1.bc2868p-3f,
- 0x1.c8ff7cp-3f, 0x1.d5c216p-3f, 0x1.e27076p-3f, 0x1.ef0adcp-3f,
- 0x1.fb9186p-3f, 0x1.04025ap-2f, 0x1.0a324ep-2f, 0x1.1058cp-2f,
- 0x1.1675cap-2f, 0x1.1c898cp-2f, 0x1.22942p-2f, 0x1.2895a2p-2f,
- 0x1.2e8e2cp-2f, 0x1.347ddap-2f, 0x1.3a64c6p-2f, 0x1.404308p-2f,
- 0x1.4618bcp-2f, 0x1.4be5fap-2f, 0x1.51aad8p-2f, 0x1.576772p-2f,
- 0x1.5d1bdcp-2f, 0x1.62c83p-2f, 0x1.686c82p-2f, 0x1.6e08eap-2f,
- 0x1.739d8p-2f, 0x1.792a56p-2f, 0x1.7eaf84p-2f, 0x1.842d1ep-2f,
- 0x1.89a338p-2f, 0x1.8f11e8p-2f, 0x1.947942p-2f, 0x1.99d958p-2f,
- 0x1.9f323ep-2f, 0x1.a4840ap-2f, 0x1.a9cecap-2f, 0x1.af1294p-2f,
- 0x1.b44f78p-2f, 0x1.b9858ap-2f, 0x1.beb4dap-2f, 0x1.c3dd7ap-2f,
- 0x1.c8ff7cp-2f, 0x1.ce1afp-2f, 0x1.d32fe8p-2f, 0x1.d83e72p-2f,
- 0x1.dd46ap-2f, 0x1.e24882p-2f, 0x1.e74426p-2f, 0x1.ec399ep-2f,
- 0x1.f128f6p-2f, 0x1.f6124p-2f, 0x1.faf588p-2f, 0x1.ffd2ep-2f,
- 0x1.02552ap-1f, 0x1.04bdfap-1f, 0x1.0723e6p-1f, 0x1.0986f4p-1f,
- 0x1.0be72ep-1f, 0x1.0e4498p-1f, 0x1.109f3ap-1f, 0x1.12f71ap-1f,
- 0x1.154c3ep-1f, 0x1.179eacp-1f, 0x1.19ee6cp-1f, 0x1.1c3b82p-1f,
- 0x1.1e85f6p-1f, 0x1.20cdcep-1f, 0x1.23130ep-1f, 0x1.2555bcp-1f,
- 0x1.2795e2p-1f, 0x1.29d38p-1f, 0x1.2c0e9ep-1f, 0x1.2e4744p-1f,
- 0x1.307d74p-1f, 0x1.32b134p-1f, 0x1.34e28ap-1f, 0x1.37117cp-1f,
- 0x1.393e0ep-1f, 0x1.3b6844p-1f, 0x1.3d9026p-1f, 0x1.3fb5b8p-1f,
- 0x1.41d8fep-1f, 0x1.43f9fep-1f, 0x1.4618bcp-1f, 0x1.48353ep-1f,
- 0x1.4a4f86p-1f, 0x1.4c679ap-1f, 0x1.4e7d82p-1f, 0x1.50913cp-1f,
- 0x1.52a2d2p-1f, 0x1.54b246p-1f, 0x1.56bf9ep-1f, 0x1.58cadcp-1f,
- 0x1.5ad404p-1f, 0x1.5cdb1ep-1f, 0x1.5ee02ap-1f, 0x1.60e33p-1f,
-};
-
LLVM_LIBC_FUNCTION(bfloat16, log_bf16, (bfloat16 x)) {
- using FPBits = fputil::FPBits<bfloat16>;
- FPBits x_bits(x);
-
- uint16_t x_u = x_bits.uintval();
-
- // If x <= 0, or x is 1, or x is +inf, or x is NaN.
- if (LIBC_UNLIKELY(x_u == 0U || x_u == 0x3f80U || x_u >= 0x7f80U)) {
- // log(NaN) = NaN
- if (x_bits.is_nan()) {
- if (x_bits.is_signaling_nan()) {
- fputil::raise_except_if_required(FE_INVALID);
- return FPBits::quiet_nan().get_val();
- }
-
- return x;
- }
-
- // log(+/-0) = −inf
- if ((x_u & 0x7fffU) == 0U) {
- fputil::raise_except_if_required(FE_DIVBYZERO);
- return FPBits::inf(Sign::NEG).get_val();
- }
-
- // log(1) = 0
- if (x_u == 0x3f80U)
- return FPBits::zero().get_val();
-
- // x < 0
- if (x_u > 0x8000U) {
- fputil::set_errno_if_required(EDOM);
- fputil::raise_except_if_required(FE_INVALID);
- return FPBits::quiet_nan().get_val();
- }
-
- // log(+inf) = +inf
- return FPBits::inf().get_val();
- }
-
-#ifndef LIBC_TARGET_CPU_HAS_FMA
- // log(0.00000000000000171390679426508540927898138761520386)
- // ~= -34.00000095
- if (LIBC_UNLIKELY(x_u == 0x26F7U))
- return bfloat16(-34.0000009);
-#endif // LIBC_TARGET_CPU_HAS_FMA
-
- int e = -FPBits::EXP_BIAS;
-
- // When x is subnormal, normalize it.
- if ((x_u & FPBits::EXP_MASK) == 0U) {
- // Can't pass an integer to fputil::cast directly.
- constexpr float NORMALIZE_EXP = 1U << FPBits::FRACTION_LEN;
- x_bits = FPBits(x_bits.get_val() * fputil::cast<bfloat16>(NORMALIZE_EXP));
- x_u = x_bits.uintval();
- e -= FPBits::FRACTION_LEN;
- }
-
- // To compute log(x), we perform the following range reduction:
- // x = 2^e * (1 + m),
- // log(x) = e * log(2) + log(1 + m).
- // for BFloat16, mantissa is at most 7 explicit bits, so we lookup
- // log(1 + m) in LOG_1_PLUS_M table using `m` as key.
-
- // Get the 7-bit mantissa directly as the table index
- uint16_t m = x_bits.get_mantissa();
-
- // Get unbiased exponent
- e += x_u >> FPBits::FRACTION_LEN;
-
- return fputil::cast<bfloat16>(
- fputil::multiply_add(static_cast<float>(e), LOGF_2, LOG_1_PLUS_M[m]));
+ return math::log_bf16(x);
}
} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/test/shared/CMakeLists.txt b/libc/test/shared/CMakeLists.txt
index 2e351d8051bed..2b169ecf93b3b 100644
--- a/libc/test/shared/CMakeLists.txt
+++ b/libc/test/shared/CMakeLists.txt
@@ -176,6 +176,7 @@ add_fp_unittest(
libc.src.__support.math.logbf128
libc.src.__support.math.logbf16
libc.src.__support.math.logf
+ libc.src.__support.math.log_bf16
libc.src.__support.math.ldexpf
libc.src.__support.math.ldexpf128
libc.src.__support.math.ldexpf16
diff --git a/libc/test/shared/shared_math_test.cpp b/libc/test/shared/shared_math_test.cpp
index 4eb950f030a1a..81a37c7f233cc 100644
--- a/libc/test/shared/shared_math_test.cpp
+++ b/libc/test/shared/shared_math_test.cpp
@@ -452,6 +452,9 @@ TEST(LlvmLibcSharedMathTest, AllBFloat16) {
EXPECT_EQ(1, LIBC_NAMESPACE::shared::setpayloadsigbf16(&setpayloadsigbf16_res,
bfloat16(0.0)));
EXPECT_FP_EQ(bfloat16(0.0), setpayloadsigbf16_res);
+
+ EXPECT_FP_EQ(bfloat16(0.0), LIBC_NAMESPACE::shared::log_bf16(bfloat16(1.0)));
+
bfloat16 neg_min_denormal = FPBits::min_subnormal(Sign::NEG).get_val();
EXPECT_FP_EQ(neg_min_denormal,
LIBC_NAMESPACE::shared::nextdownbf16(bfloat16(0.0)));
diff --git a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
index 316fda92c04a6..c357f124bed34 100644
--- a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
+++ b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
@@ -5352,6 +5352,21 @@ libc_support_library(
],
)
+libc_support_library(
+ name = "__support_math_log_bf16",
+ hdrs = ["src/__support/math/log_bf16.h"],
+ deps = [
+ ":__support_common",
+ ":__support_fputil_bfloat16",
+ ":__support_fputil_cast",
+ ":__support_fputil_fp_bits",
+ ":__support_fputil_multiply_add",
+ ":__support_macros_config",
+ ":__support_macros_optimization",
+ ":__support_macros_properties_cpu_features",
+ ],
+)
+
libc_support_library(
name = "__support_range_reduction_double",
hdrs = [
@@ -7545,6 +7560,13 @@ libc_math_function(
],
)
+libc_math_function(
+ name = "log_bf16",
+ additional_deps = [
+ ":__support_math_log_bf16",
+ ],
+)
+
libc_math_function(name = "lrint")
libc_math_function(name = "lrintf")
>From a702a6e7aca4ce815112ad3ba82b6e218c9d15fd Mon Sep 17 00:00:00 2001
From: Sukumarsawant <sawantsukumar at gmail.com>
Date: Sun, 15 Mar 2026 01:33:11 +0530
Subject: [PATCH 2/2] nit
---
libc/src/__support/math/log_bf16.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/libc/src/__support/math/log_bf16.h b/libc/src/__support/math/log_bf16.h
index 7575079770bb9..d4ab6b6af723c 100644
--- a/libc/src/__support/math/log_bf16.h
+++ b/libc/src/__support/math/log_bf16.h
@@ -134,8 +134,8 @@ LIBC_INLINE bfloat16 log_bf16(bfloat16 x) {
// Get unbiased exponent
e += x_u >> FPBits::FRACTION_LEN;
- return fputil::cast<bfloat16>(
- fputil::multiply_add(static_cast<float>(e), BF16_LOGF_2, LOG_1_PLUS_M[m]));
+ return fputil::cast<bfloat16>(fputil::multiply_add(
+ static_cast<float>(e), BF16_LOGF_2, LOG_1_PLUS_M[m]));
}
} // namespace math
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