[libc-commits] [libc] Add indirection for name-mangled expf overloads (PR #182179)
via libc-commits
libc-commits at lists.llvm.org
Wed Feb 18 15:21:44 PST 2026
https://github.com/Sterling-Augustine created https://github.com/llvm/llvm-project/pull/182179
Proof of concept for genericizing the name-mangled vector-versions of expf, to allow the vectorizer to call from C.
There is no standardized way to extract a mangled-name at compile time.
This patch use builds on the diffs in https://github.com/llvm/llvm-project/pull/173058 with changes to two files:
libc/src/mathvec/expf.h
libc/src/mathvec/generic/expf.cpp
The new usage would be something like:
simd_float_type f = __expf_simd_float(foo);
This relies on the vectorizer properly creating a cpp::vector<float> itself.
>From 76d19e90fcbb88dab8e59087135d2cea2cf4e6fc Mon Sep 17 00:00:00 2001
From: Sterling Augustine <saugustine at google.com>
Date: Wed, 18 Feb 2026 14:46:09 -0800
Subject: [PATCH 1/3] Import upstream patch
---
libc/CMakeLists.txt | 2 +
libc/config/linux/aarch64/entrypoints.txt | 9 ++
libc/config/linux/x86_64/entrypoints.txt | 9 ++
libc/lib/CMakeLists.txt | 6 +-
libc/src/CMakeLists.txt | 4 +
libc/src/__support/CMakeLists.txt | 3 +
libc/src/__support/CPP/bit.h | 2 +-
.../macros/properties/cpu_features.h | 4 +
libc/src/__support/mathvec/CMakeLists.txt | 21 +++
libc/src/__support/mathvec/common_constants.h | 40 ++++++
libc/src/__support/mathvec/expf.h | 84 +++++++++++
libc/src/__support/mathvec/expf_utils.h | 34 +++++
libc/src/mathvec/CMakeLists.txt | 43 ++++++
libc/src/mathvec/expf.h | 21 +++
libc/src/mathvec/generic/CMakeLists.txt | 12 ++
libc/src/mathvec/generic/expf.cpp | 16 +++
libc/test/UnitTest/SIMDMatcher.h | 61 ++++++++
libc/test/src/CMakeLists.txt | 4 +
libc/test/src/mathvec/CMakeLists.txt | 17 +++
libc/test/src/mathvec/expf_test.cpp | 131 ++++++++++++++++++
20 files changed, 519 insertions(+), 4 deletions(-)
create mode 100644 libc/src/__support/mathvec/CMakeLists.txt
create mode 100644 libc/src/__support/mathvec/common_constants.h
create mode 100644 libc/src/__support/mathvec/expf.h
create mode 100644 libc/src/__support/mathvec/expf_utils.h
create mode 100644 libc/src/mathvec/CMakeLists.txt
create mode 100644 libc/src/mathvec/expf.h
create mode 100644 libc/src/mathvec/generic/CMakeLists.txt
create mode 100644 libc/src/mathvec/generic/expf.cpp
create mode 100644 libc/test/UnitTest/SIMDMatcher.h
create mode 100644 libc/test/src/mathvec/CMakeLists.txt
create mode 100644 libc/test/src/mathvec/expf_test.cpp
diff --git a/libc/CMakeLists.txt b/libc/CMakeLists.txt
index 4e6b4195a9c5e..2d474f08841ca 100644
--- a/libc/CMakeLists.txt
+++ b/libc/CMakeLists.txt
@@ -350,6 +350,7 @@ include(LLVMLibCRules)
set(TARGET_LLVMLIBC_ENTRYPOINTS "")
set(TARGET_LIBC_ENTRYPOINTS "")
set(TARGET_LIBM_ENTRYPOINTS "")
+set(TARGET_LIBMVEC_ENTRYPOINTS "")
set(TARGET_LLVMLIBC_REMOVED_ENTRYPOINTS "")
# Check entrypoints.txt
@@ -380,6 +381,7 @@ foreach(removed_entrypoint IN LISTS TARGET_LLVMLIBC_REMOVED_ENTRYPOINTS)
list(REMOVE_ITEM TARGET_LLVMLIBC_ENTRYPOINTS ${removed_entrypoint})
list(REMOVE_ITEM TARGET_LIBC_ENTRYPOINTS ${removed_entrypoint})
list(REMOVE_ITEM TARGET_LIBM_ENTRYPOINTS ${removed_entrypoint})
+ list(REMOVE_ITEM TARGET_LIBMVEC_ENTRYPOINTS ${removed_entrypoint})
endforeach()
set(TARGET_ENTRYPOINT_NAME_LIST "")
diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index 970c825bbfc96..0d99a2d63d249 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -1178,7 +1178,16 @@ if(LLVM_LIBC_FULL_BUILD)
)
endif()
+set(TARGET_LIBMVEC_ENTRYPOINTS)
+
+if(LIBC_COMPILER_HAS_EXT_VECTOR_TYPE)
+ list(APPEND TARGET_LIBMVEC_ENTRYPOINTS
+ libc.src.mathvec.expf
+ )
+endif()
+
set(TARGET_LLVMLIBC_ENTRYPOINTS
${TARGET_LIBC_ENTRYPOINTS}
${TARGET_LIBM_ENTRYPOINTS}
+ ${TARGET_LIBMVEC_ENTRYPOINTS}
)
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 9399b284fa2da..6f0ecf0c6885d 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -1396,7 +1396,16 @@ if(LLVM_LIBC_FULL_BUILD)
)
endif()
+set(TARGET_LIBMVEC_ENTRYPOINTS)
+
+if(LIBC_COMPILER_HAS_EXT_VECTOR_TYPE)
+list(APPEND TARGET_LIBMVEC_ENTRYPOINTS
+ libc.src.mathvec.expf
+ )
+endif()
+
set(TARGET_LLVMLIBC_ENTRYPOINTS
${TARGET_LIBC_ENTRYPOINTS}
${TARGET_LIBM_ENTRYPOINTS}
+ ${TARGET_LIBMVEC_ENTRYPOINTS}
)
diff --git a/libc/lib/CMakeLists.txt b/libc/lib/CMakeLists.txt
index ce0b07fb6cb49..19751a9cc0736 100644
--- a/libc/lib/CMakeLists.txt
+++ b/libc/lib/CMakeLists.txt
@@ -2,10 +2,10 @@ set(libc_archive_targets "")
set(libc_archive_names "")
set(libc_archive_entrypoint_lists "")
if(LLVM_LIBC_FULL_BUILD)
- list(APPEND libc_archive_names c m)
- list(APPEND libc_archive_targets libc libm)
+ list(APPEND libc_archive_names c m mvec)
+ list(APPEND libc_archive_targets libc libm libmvec)
list(APPEND libc_archive_entrypoint_lists
- TARGET_LIBC_ENTRYPOINTS TARGET_LIBM_ENTRYPOINTS)
+ TARGET_LIBC_ENTRYPOINTS TARGET_LIBM_ENTRYPOINTS TARGET_LIBMVEC_ENTRYPOINTS)
else()
list(APPEND libc_archive_names llvmlibc)
list(APPEND libc_archive_targets libc)
diff --git a/libc/src/CMakeLists.txt b/libc/src/CMakeLists.txt
index b2afe0a33acee..8a0acccaed708 100644
--- a/libc/src/CMakeLists.txt
+++ b/libc/src/CMakeLists.txt
@@ -29,6 +29,10 @@ if(${LIBC_TARGET_OS} STREQUAL "linux")
add_subdirectory(termios)
endif()
+if(LIBC_COMPILER_HAS_EXT_VECTOR_TYPE)
+ add_subdirectory(mathvec)
+endif()
+
if(NOT LLVM_LIBC_FULL_BUILD)
return()
endif()
diff --git a/libc/src/__support/CMakeLists.txt b/libc/src/__support/CMakeLists.txt
index d771d3eb1920c..253bc27bded20 100644
--- a/libc/src/__support/CMakeLists.txt
+++ b/libc/src/__support/CMakeLists.txt
@@ -442,3 +442,6 @@ if(NOT (LIBC_TARGET_OS_IS_DARWIN))
endif()
add_subdirectory(math)
+if(LIBC_COMPILER_HAS_EXT_VECTOR_TYPE)
+ add_subdirectory(mathvec)
+endif()
diff --git a/libc/src/__support/CPP/bit.h b/libc/src/__support/CPP/bit.h
index 88d4362e6758c..ccf623a0298d9 100644
--- a/libc/src/__support/CPP/bit.h
+++ b/libc/src/__support/CPP/bit.h
@@ -39,7 +39,7 @@ LIBC_INLINE static void inline_copy(const char *from, char *to) {
// This implementation of bit_cast requires trivially-constructible To, to avoid
// UB in the implementation.
template <typename To, typename From>
-LIBC_INLINE constexpr cpp::enable_if_t<
+LIBC_INLINE static constexpr cpp::enable_if_t<
(sizeof(To) == sizeof(From)) &&
cpp::is_trivially_constructible<To>::value &&
cpp::is_trivially_copyable<To>::value &&
diff --git a/libc/src/__support/macros/properties/cpu_features.h b/libc/src/__support/macros/properties/cpu_features.h
index ce676d01577fb..08b5226feff26 100644
--- a/libc/src/__support/macros/properties/cpu_features.h
+++ b/libc/src/__support/macros/properties/cpu_features.h
@@ -56,6 +56,10 @@
#define LIBC_TARGET_CPU_HAS_AVX512BW
#endif
+#if defined(__AVX512F__) || defined(__AVX2__)
+#define LIBC_TARGET_CPU_HAS_GATHER
+#endif
+
#if defined(__ARM_FP)
#if (__ARM_FP & 0x2)
#define LIBC_TARGET_CPU_HAS_ARM_FPU_HALF
diff --git a/libc/src/__support/mathvec/CMakeLists.txt b/libc/src/__support/mathvec/CMakeLists.txt
new file mode 100644
index 0000000000000..3cd835f1f3cd1
--- /dev/null
+++ b/libc/src/__support/mathvec/CMakeLists.txt
@@ -0,0 +1,21 @@
+add_header_library(common_constants HDRS common_constants.h)
+
+add_header_library(
+ expf_utils
+ HDRS
+ expf_utils.h
+ DEPENDS
+ .common_constants
+ libc.src.__support.CPP.simd
+)
+
+add_header_library(
+ expf
+ HDRS
+ expf.h
+ DEPENDS
+ .expf_utils
+ libc.src.__support.CPP.simd
+ libc.src.__support.FPUtil.fp_bits
+ libc.src.__support.common
+)
diff --git a/libc/src/__support/mathvec/common_constants.h b/libc/src/__support/mathvec/common_constants.h
new file mode 100644
index 0000000000000..c803017ffca4c
--- /dev/null
+++ b/libc/src/__support/mathvec/common_constants.h
@@ -0,0 +1,40 @@
+//===-- Common constants for mathvec functions ------------------*- 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_MATHVEC_COMMON_CONSTANTS_H
+#define LLVM_LIBC_SRC___SUPPORT_MATHVEC_COMMON_CONSTANTS_H
+
+namespace LIBC_NAMESPACE_DECL {
+
+namespace mathvec {
+
+// Lookup table for mantissas of 2^(i / 64) with i = 0, ..., 63.
+LIBC_INLINE_VAR constexpr uint64_t EXP_MANTISSA[64] = {
+ 0x0000000000000, 0x02c9a3e778061, 0x059b0d3158574, 0x0874518759bc8,
+ 0x0b5586cf9890f, 0x0e3ec32d3d1a2, 0x11301d0125b51, 0x1429aaea92de0,
+ 0x172b83c7d517b, 0x1a35beb6fcb75, 0x1d4873168b9aa, 0x2063b88628cd6,
+ 0x2387a6e756238, 0x26b4565e27cdd, 0x29e9df51fdee1, 0x2d285a6e4030b,
+ 0x306fe0a31b715, 0x33c08b26416ff, 0x371a7373aa9cb, 0x3a7db34e59ff7,
+ 0x3dea64c123422, 0x4160a21f72e2a, 0x44e086061892d, 0x486a2b5c13cd0,
+ 0x4bfdad5362a27, 0x4f9b2769d2ca7, 0x5342b569d4f82, 0x56f4736b527da,
+ 0x5ab07dd485429, 0x5e76f15ad2148, 0x6247eb03a5585, 0x6623882552225,
+ 0x6a09e667f3bcd, 0x6dfb23c651a2f, 0x71f75e8ec5f74, 0x75feb564267c9,
+ 0x7a11473eb0187, 0x7e2f336cf4e62, 0x82589994cce13, 0x868d99b4492ed,
+ 0x8ace5422aa0db, 0x8f1ae99157736, 0x93737b0cdc5e5, 0x97d829fde4e50,
+ 0x9c49182a3f090, 0xa0c667b5de565, 0xa5503b23e255d, 0xa9e6b5579fdbf,
+ 0xae89f995ad3ad, 0xb33a2b84f15fb, 0xb7f76f2fb5e47, 0xbcc1e904bc1d2,
+ 0xc199bdd85529c, 0xc67f12e57d14b, 0xcb720dcef9069, 0xd072d4a07897c,
+ 0xd5818dcfba487, 0xda9e603db3285, 0xdfc97337b9b5f, 0xe502ee78b3ff6,
+ 0xea4afa2a490da, 0xefa1bee615a27, 0xf50765b6e4540, 0xfa7c1819e90d8,
+};
+
+} // namespace mathvec
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC___SUPPORT_MATHVEC_COMMON_CONSTANTS_H
diff --git a/libc/src/__support/mathvec/expf.h b/libc/src/__support/mathvec/expf.h
new file mode 100644
index 0000000000000..548a927d474fc
--- /dev/null
+++ b/libc/src/__support/mathvec/expf.h
@@ -0,0 +1,84 @@
+//===-- Implementation header for SIMD expf ---------------------*- 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_MATHVEC_EXPF_H
+#define LLVM_LIBC_SRC___SUPPORT_MATHVEC_EXPF_H
+
+#include "expf_utils.h"
+#include "src/__support/CPP/simd.h"
+#include "src/__support/FPUtil/FPBits.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+namespace mathvec {
+
+template <size_t N>
+LIBC_INLINE cpp::simd<double, N> static inline_exp(cpp::simd<double, N> x) {
+ constexpr cpp::simd<double, N> shift = 0x1.800000000ffc0p+46;
+
+ // inv_ln2 = round(1/log(2), D, RN);
+ constexpr cpp::simd<double, N> inv_ln2 = 0x1.71547652b82fep+0;
+ cpp::simd<double, N> z = shift + x * inv_ln2;
+ cpp::simd<double, N> n = z - shift;
+
+ // ln2_hi = round(log(2), D, RN);
+ // ln2_lo = round(log(2) - ln2_hi, D, RN);
+ constexpr cpp::simd<double, N> ln2_hi = 0x1.62e42fefa39efp-1;
+ constexpr cpp::simd<double, N> ln2_lo = 0x1.abc9e3b39803fp-56;
+
+ cpp::simd<double, N> r = x;
+ r = r - n * ln2_hi;
+ r = r - n * ln2_lo;
+
+ // Coefficients of exp approximation, generated by Sollya with:
+ // poly = 1 + x;
+ // for i from 2 to 5 do {
+ // r = remez(exp(x)-poly(x), 5-i, [-log(2)/128;log(2)/128], x^i, 1e-10);
+ // c = coeff(roundcoefficients(r, [|D ...|]), 0);
+ // poly = poly + x^i*c;
+ // c;
+ // };
+ constexpr cpp::simd<double, N> c0 = 0x1.fffffffffdbcep-2;
+ constexpr cpp::simd<double, N> c1 = 0x1.55555555543c2p-3;
+ constexpr cpp::simd<double, N> c2 = 0x1.555573c64f2e3p-5;
+ constexpr cpp::simd<double, N> c3 = 0x1.111126b4eff73p-7;
+
+ /* y = exp(r) - 1 ~= r + C0 r^2 + C1 r^3 + C2 r^4 + C3 r^5. */
+ cpp::simd<double, N> r2 = r * r;
+ cpp::simd<double, N> p01 = c0 + r * c1;
+ cpp::simd<double, N> p23 = c2 + r * c3;
+ cpp::simd<double, N> p04 = p01 + r2 * p23;
+ cpp::simd<double, N> y = r + p04 * r2;
+
+ cpp::simd<uint64_t, N> u = cpp::bit_cast<cpp::simd<uint64_t, N>>(z);
+ cpp::simd<double, N> s = exp_lookup(u);
+ return s + s * y;
+}
+
+template <size_t N>
+LIBC_INLINE cpp::simd<float, N> expf(cpp::simd<float, N> x) {
+ using FPBits = typename fputil::FPBits<float>;
+
+ cpp::simd<bool, N> is_inf = x >= 0x1.62e38p+9;
+ cpp::simd<bool, N> is_zero = x <= -0x1.628c2ap+9;
+ cpp::simd<bool, N> is_special = is_inf | is_zero;
+
+ cpp::simd<float, N> special_res = is_inf ? FPBits::inf().get_val() : 0.0f;
+
+ cpp::simd<double, N> x_d = cpp::simd_cast<double, float, N>(x);
+ cpp::simd<double, N> y = inline_exp(x_d);
+ cpp::simd<float, N> ret = cpp::simd_cast<float, double, N>(y);
+ return is_special ? special_res : ret;
+}
+
+} // namespace mathvec
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC___SUPPORT_MATHVEC_EXPF_H
diff --git a/libc/src/__support/mathvec/expf_utils.h b/libc/src/__support/mathvec/expf_utils.h
new file mode 100644
index 0000000000000..99a30c5d8fc82
--- /dev/null
+++ b/libc/src/__support/mathvec/expf_utils.h
@@ -0,0 +1,34 @@
+//===-- Common utils for exp 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_SRC___SUPPORT_MATHVEC_EXP_UTILS_H
+#define LLVM_LIBC_SRC___SUPPORT_MATHVEC_EXP_UTILS_H
+
+#include "src/__support/CPP/simd.h"
+#include "src/__support/FPUtil/FPBits.h"
+#include "src/__support/mathvec/common_constants.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+namespace mathvec {
+
+template <size_t N>
+LIBC_INLINE cpp::simd<double, N> static exp_lookup(cpp::simd<uint64_t, N> u) {
+ cpp::simd<uint64_t, N> index = u & cpp::simd<uint64_t, N>(0x3f);
+ cpp::simd<uint64_t, N> mantissa =
+ cpp::gather<cpp::simd<uint64_t, N>>(true, index, EXP_MANTISSA);
+ cpp::simd<uint64_t, N> exponent = (u >> 6) << 52;
+ cpp::simd<uint64_t, N> result = mantissa | exponent;
+ return cpp::bit_cast<cpp::simd<double, N>>(result);
+}
+
+} // namespace mathvec
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC___SUPPORT_MATHVEC_EXP_UTILS_H
diff --git a/libc/src/mathvec/CMakeLists.txt b/libc/src/mathvec/CMakeLists.txt
new file mode 100644
index 0000000000000..dff1dd3b70b51
--- /dev/null
+++ b/libc/src/mathvec/CMakeLists.txt
@@ -0,0 +1,43 @@
+add_subdirectory(generic)
+if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_ARCHITECTURE})
+ add_subdirectory(${LIBC_TARGET_ARCHITECTURE})
+endif()
+
+function(add_vector_math_entrypoint_object name)
+ # We prefer machine specific implementation if available. Hence we check
+ # that first and return early if we are able to add an alias target for the
+ # machine specific implementation.
+ get_fq_target_name("${LIBC_TARGET_ARCHITECTURE}.${name}" fq_machine_specific_target_name)
+ if(TARGET ${fq_machine_specific_target_name})
+ add_entrypoint_object(
+ ${name}
+ ALIAS
+ DEPENDS
+ .${LIBC_TARGET_ARCHITECTURE}.${name}
+ )
+ return()
+ endif()
+
+ get_fq_target_name("generic.${name}" fq_generic_target_name)
+ if(TARGET ${fq_generic_target_name})
+ add_entrypoint_object(
+ ${name}
+ ALIAS
+ DEPENDS
+ .generic.${name}
+ )
+ return()
+ endif()
+
+ # Add a dummy entrypoint object for missing implementations. They will be skipped
+ # anyway as there will be no entry for them in the target entrypoints list.
+ add_entrypoint_object(
+ ${name}
+ SRCS
+ dummy_srcs
+ HDRS
+ dummy_hdrs
+ )
+endfunction()
+
+add_vector_math_entrypoint_object(expf)
diff --git a/libc/src/mathvec/expf.h b/libc/src/mathvec/expf.h
new file mode 100644
index 0000000000000..257fb485838af
--- /dev/null
+++ b/libc/src/mathvec/expf.h
@@ -0,0 +1,21 @@
+//===-- Implementation header for SIMD expf ---------------------*- 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_MATHVEC_EXPF_H
+#define LLVM_LIBC_SRC_MATHVEC_EXPF_H
+
+#include "src/__support/CPP/simd.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+cpp::simd<float> expf(cpp::simd<float> x);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_MATHVEC_EXPF_H
diff --git a/libc/src/mathvec/generic/CMakeLists.txt b/libc/src/mathvec/generic/CMakeLists.txt
new file mode 100644
index 0000000000000..c2abbfbe265ca
--- /dev/null
+++ b/libc/src/mathvec/generic/CMakeLists.txt
@@ -0,0 +1,12 @@
+add_entrypoint_object(
+ expf
+ SRCS
+ expf.cpp
+ HDRS
+ ../expf.h
+ DEPENDS
+ libc.src.__support.mathvec.expf
+ FLAGS
+ ROUND_OPT
+ FMA_OPT
+)
diff --git a/libc/src/mathvec/generic/expf.cpp b/libc/src/mathvec/generic/expf.cpp
new file mode 100644
index 0000000000000..d86c21d40644c
--- /dev/null
+++ b/libc/src/mathvec/generic/expf.cpp
@@ -0,0 +1,16 @@
+//===-- Single-precision SIMD e^x vector 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/mathvec/expf.h"
+#include "src/__support/mathvec/expf.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+cpp::simd<float> expf(cpp::simd<float> x) { return mathvec::expf(x); }
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/test/UnitTest/SIMDMatcher.h b/libc/test/UnitTest/SIMDMatcher.h
new file mode 100644
index 0000000000000..542d311ddbd89
--- /dev/null
+++ b/libc/test/UnitTest/SIMDMatcher.h
@@ -0,0 +1,61 @@
+//===-- SIMDMatchers.h ------------------------------------------*- 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_TEST_UNITTEST_SIMDMATCHER_H
+#define LLVM_LIBC_TEST_UNITTEST_SIMDMATCHER_H
+
+#include "src/__support/FPUtil/FPBits.h"
+#include "src/__support/macros/config.h"
+#include "src/__support/macros/properties/architectures.h"
+#include "test/UnitTest/FPMatcher.h"
+#include "test/UnitTest/Test.h"
+
+#include "hdr/math_macros.h"
+
+#define EXPECT_SIMD_EQ(REF, RES) \
+ for (size_t i = 0; \
+ i < LIBC_NAMESPACE::cpp::internal::native_vector_size<float>; i++) { \
+ EXPECT_FP_EQ(REF[i], RES[i]); \
+ }
+
+#define EXPECT_SIMD_EQ_WITH_EXCEPTION(REF, RES, EXCEPTION) \
+ for (size_t i = 0; \
+ i < LIBC_NAMESPACE::cpp::internal::native_vector_size<float>; i++) { \
+ EXPECT_FP_EQ_WITH_EXCEPTION(REF[i], RES[i], EXCEPTION); \
+ }
+
+#define EXPECT_SIMD_EQ_ROUNDING_MODE(expected, actual, rounding_mode) \
+ do { \
+ using namespace LIBC_NAMESPACE::fputil::testing; \
+ ForceRoundingMode __r((rounding_mode)); \
+ if (__r.success) { \
+ EXPECT_SIMD_EQ((expected), (actual)) \
+ } \
+ } while (0)
+
+#define EXPECT_SIMD_EQ_ROUNDING_NEAREST(expected, actual) \
+ EXPECT_SIMD_EQ_ROUNDING_MODE((expected), (actual), RoundingMode::Nearest)
+
+#define EXPECT_SIMD_EQ_ROUNDING_UPWARD(expected, actual) \
+ EXPECT_SIMD_EQ_ROUNDING_MODE((expected), (actual), RoundingMode::Upward)
+
+#define EXPECT_SIMD_EQ_ROUNDING_DOWNWARD(expected, actual) \
+ EXPECT_SIMD_EQ_ROUNDING_MODE((expected), (actual), RoundingMode::Downward)
+
+#define EXPECT_SIMD_EQ_ROUNDING_TOWARD_ZERO(expected, actual) \
+ EXPECT_SIMD_EQ_ROUNDING_MODE((expected), (actual), RoundingMode::TowardZero)
+
+#define EXPECT_SIMD_EQ_ALL_ROUNDING(expected, actual) \
+ do { \
+ EXPECT_SIMD_EQ_ROUNDING_NEAREST((expected), (actual)); \
+ EXPECT_SIMD_EQ_ROUNDING_UPWARD((expected), (actual)); \
+ EXPECT_SIMD_EQ_ROUNDING_DOWNWARD((expected), (actual)); \
+ EXPECT_SIMD_EQ_ROUNDING_TOWARD_ZERO((expected), (actual)); \
+ } while (0)
+
+#endif // LLVM_LIBC_TEST_UNITTEST_SIMDMATCHER_H
diff --git a/libc/test/src/CMakeLists.txt b/libc/test/src/CMakeLists.txt
index 0c6ec9f07a9b7..5e61c739c066a 100644
--- a/libc/test/src/CMakeLists.txt
+++ b/libc/test/src/CMakeLists.txt
@@ -87,6 +87,10 @@ if(${LIBC_TARGET_OS} STREQUAL "linux")
add_subdirectory(termios)
endif()
+if(LIBC_COMPILER_HAS_EXT_VECTOR_TYPE)
+ add_subdirectory(mathvec)
+endif()
+
if(NOT LLVM_LIBC_FULL_BUILD)
return()
endif()
diff --git a/libc/test/src/mathvec/CMakeLists.txt b/libc/test/src/mathvec/CMakeLists.txt
new file mode 100644
index 0000000000000..475c03877ceb1
--- /dev/null
+++ b/libc/test/src/mathvec/CMakeLists.txt
@@ -0,0 +1,17 @@
+add_custom_target(libc-mathvec-unittests)
+
+add_fp_unittest(
+ expf_test
+ SUITE
+ libc-mathvec-unittests
+ SRCS
+ expf_test.cpp
+ DEPENDS
+ libc.src.math.expf
+ libc.src.mathvec.expf
+ libc.src.__support.FPUtil.fp_bits
+ libc.src.__support.CPP.simd
+ FLAGS
+ ROUND_OPT
+ FMA_OPT
+)
diff --git a/libc/test/src/mathvec/expf_test.cpp b/libc/test/src/mathvec/expf_test.cpp
new file mode 100644
index 0000000000000..d7a4e148e8acd
--- /dev/null
+++ b/libc/test/src/mathvec/expf_test.cpp
@@ -0,0 +1,131 @@
+//===-- Unittests for expf ------------------------------------------------===//
+//
+// 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 "hdr/math_macros.h"
+#include "src/__support/CPP/simd.h"
+#include "src/__support/FPUtil/FPBits.h"
+#include "src/math/expf.h"
+#include "src/mathvec/expf.h"
+#include "test/UnitTest/SIMDMatcher.h"
+#include "test/UnitTest/Test.h"
+
+#include "hdr/stdint_proxy.h"
+
+using LlvmLibcVecExpfTest = LIBC_NAMESPACE::testing::FPTest<float>;
+
+// Wrappers
+
+// In order to test vector we can either duplicate a scalar input
+// or do something more elaborate. In any case that requires a wrapper
+// since the function call is written in this file.
+
+// Run reference on a vector with lanes duplicated from a scalar input.
+
+// with control lane
+static LIBC_NAMESPACE::cpp::simd<float> wrap_ref_vexpf(float x, float control) {
+ LIBC_NAMESPACE::cpp::simd<float> v(x);
+ v[0] = control;
+ constexpr size_t N = LIBC_NAMESPACE::cpp::internal::native_vector_size<float>;
+ for (size_t i = 0; i < N; i++)
+ v[i] = LIBC_NAMESPACE::expf(v[i]);
+ return v;
+}
+
+// without control lane
+static LIBC_NAMESPACE::cpp::simd<float> wrap_ref_vexpf(float x) {
+ return wrap_ref_vexpf(x, x);
+}
+
+// Run implementation on a vector with lanes duplicated from a scalar input.
+
+// with control lane
+static LIBC_NAMESPACE::cpp::simd<float> wrap_vexpf(float x, float control) {
+ LIBC_NAMESPACE::cpp::simd<float> v(x);
+ v[0] = control;
+ return LIBC_NAMESPACE::expf(v);
+}
+
+// without control lane
+static LIBC_NAMESPACE::cpp::simd<float> wrap_vexpf(float x) {
+ return wrap_vexpf(x, x);
+}
+
+TEST_F(LlvmLibcVecExpfTest, SpecialNumbers) {
+ EXPECT_SIMD_EQ(LIBC_NAMESPACE::cpp::splat(aNaN), wrap_vexpf(aNaN));
+
+ EXPECT_SIMD_EQ(LIBC_NAMESPACE::cpp::splat(inf), wrap_vexpf(inf));
+
+ EXPECT_SIMD_EQ(LIBC_NAMESPACE::cpp::splat(0.0f), wrap_vexpf(neg_inf));
+
+ EXPECT_SIMD_EQ(LIBC_NAMESPACE::cpp::splat(1.0f), wrap_vexpf(0.0f));
+
+ EXPECT_SIMD_EQ(LIBC_NAMESPACE::cpp::splat(1.0f), wrap_vexpf(-0.0f));
+}
+
+TEST_F(LlvmLibcVecExpfTest, Overflow) {
+ // Fails if tested with exceptions
+ EXPECT_SIMD_EQ(LIBC_NAMESPACE::cpp::splat(inf),
+ wrap_vexpf(FPBits(0x7f7fffffU).get_val()));
+
+ EXPECT_SIMD_EQ(LIBC_NAMESPACE::cpp::splat(inf),
+ wrap_vexpf(FPBits(0x42cffff8U).get_val()));
+
+ EXPECT_SIMD_EQ(LIBC_NAMESPACE::cpp::splat(inf),
+ wrap_vexpf(FPBits(0x42d00008U).get_val()));
+}
+
+TEST_F(LlvmLibcVecExpfTest, Underflow) {
+ // Passes if tested with exceptions ?
+ EXPECT_SIMD_EQ_WITH_EXCEPTION(LIBC_NAMESPACE::cpp::splat(0.0f),
+ wrap_vexpf(FPBits(0xff7fffffU).get_val()),
+ FE_UNDERFLOW);
+
+ float x = FPBits(0xc2cffff8U).get_val();
+ EXPECT_SIMD_EQ(wrap_ref_vexpf(x, 1.0), wrap_vexpf(x, 1.0));
+
+ x = FPBits(0xc2d00008U).get_val();
+ EXPECT_SIMD_EQ(wrap_ref_vexpf(x, 1.0), wrap_vexpf(x, 1.0));
+}
+
+// Test with inputs which are the borders of underflow/overflow but still
+// produce valid results without setting errno.
+// Is this still relevant to vector function?
+TEST_F(LlvmLibcVecExpfTest, Borderline) {
+ float x;
+
+ x = FPBits(0x42affff8U).get_val();
+ EXPECT_SIMD_EQ(wrap_ref_vexpf(x, 1.0), wrap_vexpf(x, 1.0));
+
+ x = FPBits(0x42b00008U).get_val();
+ EXPECT_SIMD_EQ(wrap_ref_vexpf(x, 1.0), wrap_vexpf(x, 1.0));
+
+ x = FPBits(0xc2affff8U).get_val();
+ EXPECT_SIMD_EQ(wrap_ref_vexpf(x, 1.0), wrap_vexpf(x, 1.0));
+
+ x = FPBits(0xc2b00008U).get_val();
+ EXPECT_SIMD_EQ(wrap_ref_vexpf(x, 1.0), wrap_vexpf(x, 1.0));
+
+ x = FPBits(0xc236bd8cU).get_val();
+ EXPECT_SIMD_EQ(wrap_ref_vexpf(x, 1.0), wrap_vexpf(x, 1.0));
+}
+
+TEST_F(LlvmLibcVecExpfTest, InFloatRange) {
+ constexpr uint32_t COUNT = 100'000;
+ constexpr uint32_t STEP = UINT32_MAX / COUNT;
+ for (uint32_t i = 0, v = 0; i <= COUNT; ++i, v += STEP) {
+ float x = FPBits(v).get_val();
+ if (FPBits(v).is_nan() || FPBits(v).is_inf())
+ continue;
+ EXPECT_SIMD_EQ(wrap_ref_vexpf(x), wrap_vexpf(x));
+ EXPECT_SIMD_EQ(wrap_ref_vexpf(x, aNaN), wrap_vexpf(x, aNaN));
+ EXPECT_SIMD_EQ(wrap_ref_vexpf(x, inf), wrap_vexpf(x, inf));
+ EXPECT_SIMD_EQ(wrap_ref_vexpf(x, -inf), wrap_vexpf(x, neg_inf));
+ EXPECT_SIMD_EQ(wrap_ref_vexpf(x, 0.0), wrap_vexpf(x, 0.0));
+ EXPECT_SIMD_EQ(wrap_ref_vexpf(x, -0.0), wrap_vexpf(x, -0.0));
+ }
+}
>From 55dfe1070efeea044f934cb0a310857d54d8f120 Mon Sep 17 00:00:00 2001
From: Sterling Augustine <saugustine at google.com>
Date: Wed, 18 Feb 2026 14:47:34 -0800
Subject: [PATCH 2/3] POC of Export mangled-vector-expf to C.
---
libc/src/mathvec/expf.h | 10 ++++++++++
libc/src/mathvec/generic/expf.cpp | 15 +++++++++++++++
2 files changed, 25 insertions(+)
diff --git a/libc/src/mathvec/expf.h b/libc/src/mathvec/expf.h
index 257fb485838af..5cc208692986f 100644
--- a/libc/src/mathvec/expf.h
+++ b/libc/src/mathvec/expf.h
@@ -16,6 +16,16 @@ namespace LIBC_NAMESPACE_DECL {
cpp::simd<float> expf(cpp::simd<float> x);
+// What plain C-type corresponds to cpp::simd<float>? Replace uint64_t with
+// that, then uncomment the static assert. We have to trust the callers to
+// build the type properly, which is type unsafe.
+using cpp_simd_float = uint64_t;
+// static_assert(sizeof(cpp_simd_float) == sizeof(cpp::simd<float>));
+static_assert(cpp::is_trivially_copyable<cpp::simd<float>>::value == true);
+static_assert(cpp::is_trivially_copyable<cpp_simd_float>::value == true);
+using expf_simd_float_ftype = cpp_simd_float (*)(cpp_simd_float);
} // namespace LIBC_NAMESPACE_DECL
+extern LIBC_NAMESPACE::expf_simd_float_ftype __expf_cpp_simd_float;
+
#endif // LLVM_LIBC_SRC_MATHVEC_EXPF_H
diff --git a/libc/src/mathvec/generic/expf.cpp b/libc/src/mathvec/generic/expf.cpp
index d86c21d40644c..8491df9b2bedb 100644
--- a/libc/src/mathvec/generic/expf.cpp
+++ b/libc/src/mathvec/generic/expf.cpp
@@ -8,9 +8,24 @@
#include "src/mathvec/expf.h"
#include "src/__support/mathvec/expf.h"
+#include <typeinfo>
namespace LIBC_NAMESPACE_DECL {
cpp::simd<float> expf(cpp::simd<float> x) { return mathvec::expf(x); }
+#ifdef __clang__
+#define EXPF_MANGLED_NAME _ZN22__llvm_libc_22_0_0_git5expfEDv8_f
+#else
+#ifdef __some_other_compiler__
+#define EXPF_MANGLED_NAME other_mangled_name
+#endif
+#endif
+void *EXPF_MANGLED_NAME;
+void *mangled_fn_name = &EXPF_MANGLED_NAME;
+
} // namespace LIBC_NAMESPACE_DECL
+
+LIBC_NAMESPACE::expf_simd_float_ftype __expf_simd_float =
+ reinterpret_cast<LIBC_NAMESPACE::expf_simd_float_ftype>(
+ &LIBC_NAMESPACE::EXPF_MANGLED_NAME);
>From f6c9f3c1c5f3c7903d0a81cefd2afecc9b404d49 Mon Sep 17 00:00:00 2001
From: Sterling Augustine <saugustine at google.com>
Date: Wed, 18 Feb 2026 15:08:26 -0800
Subject: [PATCH 3/3] Add some constification
---
libc/src/mathvec/expf.h | 2 +-
libc/src/mathvec/generic/expf.cpp | 5 ++---
2 files changed, 3 insertions(+), 4 deletions(-)
diff --git a/libc/src/mathvec/expf.h b/libc/src/mathvec/expf.h
index 5cc208692986f..ad1678a7a0161 100644
--- a/libc/src/mathvec/expf.h
+++ b/libc/src/mathvec/expf.h
@@ -26,6 +26,6 @@ static_assert(cpp::is_trivially_copyable<cpp_simd_float>::value == true);
using expf_simd_float_ftype = cpp_simd_float (*)(cpp_simd_float);
} // namespace LIBC_NAMESPACE_DECL
-extern LIBC_NAMESPACE::expf_simd_float_ftype __expf_cpp_simd_float;
+extern const LIBC_NAMESPACE::expf_simd_float_ftype __expf_cpp_simd_float;
#endif // LLVM_LIBC_SRC_MATHVEC_EXPF_H
diff --git a/libc/src/mathvec/generic/expf.cpp b/libc/src/mathvec/generic/expf.cpp
index 8491df9b2bedb..113f8474b3743 100644
--- a/libc/src/mathvec/generic/expf.cpp
+++ b/libc/src/mathvec/generic/expf.cpp
@@ -21,11 +21,10 @@ cpp::simd<float> expf(cpp::simd<float> x) { return mathvec::expf(x); }
#define EXPF_MANGLED_NAME other_mangled_name
#endif
#endif
-void *EXPF_MANGLED_NAME;
-void *mangled_fn_name = &EXPF_MANGLED_NAME;
+extern expf_simd_float_ftype EXPF_MANGLED_NAME;
} // namespace LIBC_NAMESPACE_DECL
-LIBC_NAMESPACE::expf_simd_float_ftype __expf_simd_float =
+extern const LIBC_NAMESPACE::expf_simd_float_ftype __expf_simd_float =
reinterpret_cast<LIBC_NAMESPACE::expf_simd_float_ftype>(
&LIBC_NAMESPACE::EXPF_MANGLED_NAME);
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