[libc-commits] [libc] d08a801 - [libc] Implement correctly rounded logf based on RLIBM library.
Tue Ly via libc-commits
libc-commits at lists.llvm.org
Thu Dec 16 10:43:38 PST 2021
Author: Tue Ly
Date: 2021-12-16T13:43:15-05:00
New Revision: d08a801b5f5678af52c89d202e5f22e0d43a38cd
URL: https://github.com/llvm/llvm-project/commit/d08a801b5f5678af52c89d202e5f22e0d43a38cd
DIFF: https://github.com/llvm/llvm-project/commit/d08a801b5f5678af52c89d202e5f22e0d43a38cd.diff
LOG: [libc] Implement correctly rounded logf based on RLIBM library.
Implement correctly rounded logf based on RLIBM library: https://people.cs.rutgers.edu/~sn349/rlibm/.
Reviewed By: sivachandra, santoshn, jpl169, zimmermann6
Differential Revision: https://reviews.llvm.org/D115408
Added:
libc/src/math/generic/logf.cpp
libc/src/math/logf.h
libc/test/src/math/differential_testing/logf_diff.cpp
libc/test/src/math/differential_testing/logf_perf.cpp
libc/test/src/math/exhaustive/logf_test.cpp
libc/test/src/math/logf_test.cpp
Modified:
libc/config/linux/aarch64/entrypoints.txt
libc/config/linux/x86_64/entrypoints.txt
libc/config/windows/entrypoints.txt
libc/spec/stdc.td
libc/src/math/CMakeLists.txt
libc/src/math/generic/CMakeLists.txt
libc/test/src/math/CMakeLists.txt
libc/test/src/math/differential_testing/CMakeLists.txt
libc/test/src/math/exhaustive/CMakeLists.txt
libc/utils/MPFRWrapper/MPFRUtils.cpp
libc/utils/MPFRWrapper/MPFRUtils.h
Removed:
################################################################################
diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index 937cc531049ec..25dc646764541 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -136,6 +136,7 @@ set(TARGET_LIBM_ENTRYPOINTS
libc.src.math.ldexp
libc.src.math.ldexpf
libc.src.math.ldexpl
+ libc.src.math.logf
libc.src.math.logb
libc.src.math.logbf
libc.src.math.logbl
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index a7d737e4e80f9..38586a4eddce7 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -140,6 +140,7 @@ set(TARGET_LIBM_ENTRYPOINTS
libc.src.math.llround
libc.src.math.llroundf
libc.src.math.llroundl
+ libc.src.math.logf
libc.src.math.logb
libc.src.math.logbf
libc.src.math.logbl
diff --git a/libc/config/windows/entrypoints.txt b/libc/config/windows/entrypoints.txt
index 995d7d9af8101..00bf38ae2dcdf 100644
--- a/libc/config/windows/entrypoints.txt
+++ b/libc/config/windows/entrypoints.txt
@@ -118,6 +118,7 @@ set(TARGET_LIBM_ENTRYPOINTS
libc.src.math.llround
libc.src.math.llroundf
libc.src.math.llroundl
+ libc.src.math.logf
libc.src.math.logb
libc.src.math.logbf
libc.src.math.logbl
diff --git a/libc/spec/stdc.td b/libc/spec/stdc.td
index 6a11b37163de2..671f76d3c6be3 100644
--- a/libc/spec/stdc.td
+++ b/libc/spec/stdc.td
@@ -396,6 +396,8 @@ def StdC : StandardSpec<"stdc"> {
FunctionSpec<"ldexpf", RetValSpec<FloatType>, [ArgSpec<FloatType>, ArgSpec<IntType>]>,
FunctionSpec<"ldexpl", RetValSpec<LongDoubleType>, [ArgSpec<LongDoubleType>, ArgSpec<IntType>]>,
+ FunctionSpec<"logf", RetValSpec<FloatType>, [ArgSpec<FloatType>]>,
+
FunctionSpec<"logb", RetValSpec<DoubleType>, [ArgSpec<DoubleType>]>,
FunctionSpec<"logbf", RetValSpec<FloatType>, [ArgSpec<FloatType>]>,
FunctionSpec<"logbl", RetValSpec<LongDoubleType>, [ArgSpec<LongDoubleType>]>,
diff --git a/libc/src/math/CMakeLists.txt b/libc/src/math/CMakeLists.txt
index b9ad660d1e57f..1a78129400758 100644
--- a/libc/src/math/CMakeLists.txt
+++ b/libc/src/math/CMakeLists.txt
@@ -116,6 +116,8 @@ add_math_entrypoint_object(ldexp)
add_math_entrypoint_object(ldexpf)
add_math_entrypoint_object(ldexpl)
+add_math_entrypoint_object(logf)
+
add_math_entrypoint_object(logb)
add_math_entrypoint_object(logbf)
add_math_entrypoint_object(logbl)
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index 6728e44e635fb..18123c21ab4bf 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -645,6 +645,18 @@ add_entrypoint_object(
-O2
)
+add_entrypoint_object(
+ logf
+ SRCS
+ logf.cpp
+ HDRS
+ ../logf.h
+ DEPENDS
+ libc.src.__support.FPUtil.fputil
+ COMPILE_OPTIONS
+ -O3
+)
+
add_entrypoint_object(
logb
SRCS
diff --git a/libc/src/math/generic/logf.cpp b/libc/src/math/generic/logf.cpp
new file mode 100644
index 0000000000000..523045ffa684f
--- /dev/null
+++ b/libc/src/math/generic/logf.cpp
@@ -0,0 +1,202 @@
+//===-- Single-precision log(x) 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/math/logf.h"
+#include "src/__support/FPUtil/BasicOperations.h"
+#include "src/__support/FPUtil/FMA.h"
+#include "src/__support/FPUtil/FPBits.h"
+#include "src/__support/FPUtil/PolyEval.h"
+#include "src/__support/common.h"
+
+// This is a correctly-rounded algorithm for log(x) in single precision with
+// round-to-nearest, tie-to-even mode from the RLIBM project at:
+// https://people.cs.rutgers.edu/~sn349/rlibm
+
+// Step 1 - Range reduction:
+// For x = 2^m * 1.mant, log(x) = m * log(2) + log(1.m)
+// If x is denormal, we normalize it by multiplying x by 2^23 and subtracting
+// m by 23.
+
+// Step 2 - Another range reduction:
+// To compute log(1.mant), let f be the highest 8 bits including the hidden
+// bit, and d be the
diff erence (1.mant - f), i.e. the remaining 16 bits of the
+// mantissa. Then we have the following approximation formula:
+// log(1.mant) = log(f) + log(1.mant / f)
+// = log(f) + log(1 + d/f)
+// ~ log(f) + P(d/f)
+// since d/f is sufficiently small.
+// log(f) and 1/f are then stored in two 2^7 = 128 entries look-up tables.
+
+// Step 3 - Polynomial approximation:
+// To compute P(d/f), we use a single degree-5 polynomial in double precision
+// which provides correct rounding for all but few exception values.
+// For more detail about how this polynomial is obtained, please refer to the
+// paper:
+// Lim, J. and Nagarakatte, S., "One Polynomial Approximation to Produce
+// Correctly Rounded Results of an Elementary Function for Multiple
+// Representations and Rounding Modes", Proceedings of the 49th ACM SIGPLAN
+// Symposium on Principles of Programming Languages (POPL-2022), Philadelphia,
+// USA, January 16-22, 2022.
+// https://people.cs.rutgers.edu/~sn349/papers/rlibmall-popl-2022.pdf
+
+namespace __llvm_libc {
+
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wc++17-extensions"
+
+// Lookup table for log(f) = log(1 + n*2^(-7)) where n = 0..127.
+static constexpr double LOG_F[128] = {
+ 0x0.0000000000000p+0, 0x1.fe02a6b106788p-8, 0x1.fc0a8b0fc03e3p-7,
+ 0x1.7b91b07d5b11ap-6, 0x1.f829b0e783300p-6, 0x1.39e87b9febd5fp-5,
+ 0x1.77458f632dcfcp-5, 0x1.b42dd711971bep-5, 0x1.f0a30c01162a6p-5,
+ 0x1.16536eea37ae0p-4, 0x1.341d7961bd1d0p-4, 0x1.51b073f06183fp-4,
+ 0x1.6f0d28ae56b4bp-4, 0x1.8c345d6319b20p-4, 0x1.a926d3a4ad563p-4,
+ 0x1.c5e548f5bc743p-4, 0x1.e27076e2af2e5p-4, 0x1.fec9131dbeabap-4,
+ 0x1.0d77e7cd08e59p-3, 0x1.1b72ad52f67a0p-3, 0x1.29552f81ff523p-3,
+ 0x1.371fc201e8f74p-3, 0x1.44d2b6ccb7d1ep-3, 0x1.526e5e3a1b437p-3,
+ 0x1.5ff3070a793d3p-3, 0x1.6d60fe719d21cp-3, 0x1.7ab890210d909p-3,
+ 0x1.87fa06520c910p-3, 0x1.9525a9cf456b4p-3, 0x1.a23bc1fe2b563p-3,
+ 0x1.af3c94e80bff2p-3, 0x1.bc286742d8cd6p-3, 0x1.c8ff7c79a9a21p-3,
+ 0x1.d5c216b4fbb91p-3, 0x1.e27076e2af2e5p-3, 0x1.ef0adcbdc5936p-3,
+ 0x1.fb9186d5e3e2ap-3, 0x1.0402594b4d040p-2, 0x1.0a324e27390e3p-2,
+ 0x1.1058bf9ae4ad5p-2, 0x1.1675cababa60ep-2, 0x1.1c898c16999fap-2,
+ 0x1.22941fbcf7965p-2, 0x1.2895a13de86a3p-2, 0x1.2e8e2bae11d30p-2,
+ 0x1.347dd9a987d54p-2, 0x1.3a64c556945e9p-2, 0x1.404308686a7e3p-2,
+ 0x1.4618bc21c5ec2p-2, 0x1.4be5f957778a0p-2, 0x1.51aad872df82dp-2,
+ 0x1.5767717455a6cp-2, 0x1.5d1bdbf5809cap-2, 0x1.62c82f2b9c795p-2,
+ 0x1.686c81e9b14aep-2, 0x1.6e08eaa2ba1e3p-2, 0x1.739d7f6bbd006p-2,
+ 0x1.792a55fdd47a2p-2, 0x1.7eaf83b82afc3p-2, 0x1.842d1da1e8b17p-2,
+ 0x1.89a3386c1425ap-2, 0x1.8f11e873662c7p-2, 0x1.947941c2116fap-2,
+ 0x1.99d958117e08ap-2, 0x1.9f323ecbf984bp-2, 0x1.a484090e5bb0ap-2,
+ 0x1.a9cec9a9a0849p-2, 0x1.af1293247786bp-2, 0x1.b44f77bcc8f62p-2,
+ 0x1.b9858969310fbp-2, 0x1.beb4d9da71b7bp-2, 0x1.c3dd7a7cdad4dp-2,
+ 0x1.c8ff7c79a9a21p-2, 0x1.ce1af0b85f3ebp-2, 0x1.d32fe7e00ebd5p-2,
+ 0x1.d83e7258a2f3ep-2, 0x1.dd46a04c1c4a0p-2, 0x1.e24881a7c6c26p-2,
+ 0x1.e744261d68787p-2, 0x1.ec399d2468cc0p-2, 0x1.f128f5faf06ecp-2,
+ 0x1.f6123fa7028acp-2, 0x1.faf588f78f31ep-2, 0x1.ffd2e0857f498p-2,
+ 0x1.02552a5a5d0fep-1, 0x1.04bdf9da926d2p-1, 0x1.0723e5c1cdf40p-1,
+ 0x1.0986f4f573520p-1, 0x1.0be72e4252a82p-1, 0x1.0e44985d1cc8bp-1,
+ 0x1.109f39e2d4c96p-1, 0x1.12f719593efbcp-1, 0x1.154c3d2f4d5e9p-1,
+ 0x1.179eabbd899a0p-1, 0x1.19ee6b467c96ep-1, 0x1.1c3b81f713c24p-1,
+ 0x1.1e85f5e7040d0p-1, 0x1.20cdcd192ab6dp-1, 0x1.23130d7bebf42p-1,
+ 0x1.2555bce98f7cbp-1, 0x1.2795e1289b11ap-1, 0x1.29d37fec2b08ap-1,
+ 0x1.2c0e9ed448e8bp-1, 0x1.2e47436e40268p-1, 0x1.307d7334f10bep-1,
+ 0x1.32b1339121d71p-1, 0x1.34e289d9ce1d3p-1, 0x1.37117b54747b5p-1,
+ 0x1.393e0d3562a19p-1, 0x1.3b68449fffc22p-1, 0x1.3d9026a7156fap-1,
+ 0x1.3fb5b84d16f42p-1, 0x1.41d8fe84672aep-1, 0x1.43f9fe2f9ce67p-1,
+ 0x1.4618bc21c5ec2p-1, 0x1.48353d1ea88dfp-1, 0x1.4a4f85db03ebbp-1,
+ 0x1.4c679afccee39p-1, 0x1.4e7d811b75bb0p-1, 0x1.50913cc01686bp-1,
+ 0x1.52a2d265bc5aap-1, 0x1.54b2467999497p-1, 0x1.56bf9d5b3f399p-1,
+ 0x1.58cadb5cd7989p-1, 0x1.5ad404c359f2cp-1, 0x1.5cdb1dc6c1764p-1,
+ 0x1.5ee02a9241675p-1, 0x1.60e32f44788d8p-1};
+
+// Lookup table for (1/f) where f = 1 + n*2^(-7), n = 0..127.
+static constexpr double ONE_OVER_F[128] = {
+ 0x1.0000000000000p+0, 0x1.fc07f01fc07f0p-1, 0x1.f81f81f81f820p-1,
+ 0x1.f44659e4a4271p-1, 0x1.f07c1f07c1f08p-1, 0x1.ecc07b301ecc0p-1,
+ 0x1.e9131abf0b767p-1, 0x1.e573ac901e574p-1, 0x1.e1e1e1e1e1e1ep-1,
+ 0x1.de5d6e3f8868ap-1, 0x1.dae6076b981dbp-1, 0x1.d77b654b82c34p-1,
+ 0x1.d41d41d41d41dp-1, 0x1.d0cb58f6ec074p-1, 0x1.cd85689039b0bp-1,
+ 0x1.ca4b3055ee191p-1, 0x1.c71c71c71c71cp-1, 0x1.c3f8f01c3f8f0p-1,
+ 0x1.c0e070381c0e0p-1, 0x1.bdd2b899406f7p-1, 0x1.bacf914c1bad0p-1,
+ 0x1.b7d6c3dda338bp-1, 0x1.b4e81b4e81b4fp-1, 0x1.b2036406c80d9p-1,
+ 0x1.af286bca1af28p-1, 0x1.ac5701ac5701bp-1, 0x1.a98ef606a63bep-1,
+ 0x1.a6d01a6d01a6dp-1, 0x1.a41a41a41a41ap-1, 0x1.a16d3f97a4b02p-1,
+ 0x1.9ec8e951033d9p-1, 0x1.9c2d14ee4a102p-1, 0x1.999999999999ap-1,
+ 0x1.970e4f80cb872p-1, 0x1.948b0fcd6e9e0p-1, 0x1.920fb49d0e229p-1,
+ 0x1.8f9c18f9c18fap-1, 0x1.8d3018d3018d3p-1, 0x1.8acb90f6bf3aap-1,
+ 0x1.886e5f0abb04ap-1, 0x1.8618618618618p-1, 0x1.83c977ab2beddp-1,
+ 0x1.8181818181818p-1, 0x1.7f405fd017f40p-1, 0x1.7d05f417d05f4p-1,
+ 0x1.7ad2208e0ecc3p-1, 0x1.78a4c8178a4c8p-1, 0x1.767dce434a9b1p-1,
+ 0x1.745d1745d1746p-1, 0x1.724287f46debcp-1, 0x1.702e05c0b8170p-1,
+ 0x1.6e1f76b4337c7p-1, 0x1.6c16c16c16c17p-1, 0x1.6a13cd1537290p-1,
+ 0x1.6816816816817p-1, 0x1.661ec6a5122f9p-1, 0x1.642c8590b2164p-1,
+ 0x1.623fa77016240p-1, 0x1.6058160581606p-1, 0x1.5e75bb8d015e7p-1,
+ 0x1.5c9882b931057p-1, 0x1.5ac056b015ac0p-1, 0x1.58ed2308158edp-1,
+ 0x1.571ed3c506b3ap-1, 0x1.5555555555555p-1, 0x1.5390948f40febp-1,
+ 0x1.51d07eae2f815p-1, 0x1.5015015015015p-1, 0x1.4e5e0a72f0539p-1,
+ 0x1.4cab88725af6ep-1, 0x1.4afd6a052bf5bp-1, 0x1.49539e3b2d067p-1,
+ 0x1.47ae147ae147bp-1, 0x1.460cbc7f5cf9ap-1, 0x1.446f86562d9fbp-1,
+ 0x1.42d6625d51f87p-1, 0x1.4141414141414p-1, 0x1.3fb013fb013fbp-1,
+ 0x1.3e22cbce4a902p-1, 0x1.3c995a47babe7p-1, 0x1.3b13b13b13b14p-1,
+ 0x1.3991c2c187f63p-1, 0x1.3813813813814p-1, 0x1.3698df3de0748p-1,
+ 0x1.3521cfb2b78c1p-1, 0x1.33ae45b57bcb2p-1, 0x1.323e34a2b10bfp-1,
+ 0x1.30d190130d190p-1, 0x1.2f684bda12f68p-1, 0x1.2e025c04b8097p-1,
+ 0x1.2c9fb4d812ca0p-1, 0x1.2b404ad012b40p-1, 0x1.29e4129e4129ep-1,
+ 0x1.288b01288b013p-1, 0x1.27350b8812735p-1, 0x1.25e22708092f1p-1,
+ 0x1.2492492492492p-1, 0x1.23456789abcdfp-1, 0x1.21fb78121fb78p-1,
+ 0x1.20b470c67c0d9p-1, 0x1.1f7047dc11f70p-1, 0x1.1e2ef3b3fb874p-1,
+ 0x1.1cf06ada2811dp-1, 0x1.1bb4a4046ed29p-1, 0x1.1a7b9611a7b96p-1,
+ 0x1.19453808ca29cp-1, 0x1.1811811811812p-1, 0x1.16e0689427379p-1,
+ 0x1.15b1e5f75270dp-1, 0x1.1485f0e0acd3bp-1, 0x1.135c81135c811p-1,
+ 0x1.12358e75d3033p-1, 0x1.1111111111111p-1, 0x1.0fef010fef011p-1,
+ 0x1.0ecf56be69c90p-1, 0x1.0db20a88f4696p-1, 0x1.0c9714fbcda3bp-1,
+ 0x1.0b7e6ec259dc8p-1, 0x1.0a6810a6810a7p-1, 0x1.0953f39010954p-1,
+ 0x1.0842108421084p-1, 0x1.073260a47f7c6p-1, 0x1.0624dd2f1a9fcp-1,
+ 0x1.05197f7d73404p-1, 0x1.0410410410410p-1, 0x1.03091b51f5e1ap-1,
+ 0x1.0204081020408p-1, 0x1.0101010101010p-1};
+
+INLINE_FMA
+LLVM_LIBC_FUNCTION(float, logf, (float x)) {
+ constexpr double LOG_2 = 0x1.62e42fefa39efp-1;
+ using FPBits = typename fputil::FPBits<float>;
+ FPBits xbits(x);
+ int m = 0;
+
+ if (xbits.uintval() < FPBits::MIN_NORMAL ||
+ xbits.uintval() > FPBits::MAX_NORMAL) {
+ if (xbits.is_zero()) {
+ return static_cast<float>(FPBits::neg_inf());
+ }
+ if (xbits.get_sign() && !xbits.is_nan()) {
+ return FPBits::build_nan(1 << (fputil::MantissaWidth<float>::VALUE - 1));
+ }
+ if (xbits.is_inf_or_nan()) {
+ return x;
+ }
+ // Normalize denormal inputs.
+ xbits.val *= 0x1.0p23f;
+ m = -23;
+ }
+
+ m += xbits.get_exponent();
+ // Set bits to 1.m
+ xbits.set_unbiased_exponent(0x7F);
+ int fIndex = xbits.get_mantissa() >> 16;
+
+ FPBits f(xbits.val);
+ f.bits &= ~0x0000'FFFF;
+
+ double d = static_cast<float>(xbits) - static_cast<float>(f);
+ d *= ONE_OVER_F[fIndex];
+
+ double r = __llvm_libc::fputil::polyeval(
+ d, 0x1.0000000008169p+0, -0x1.0000004f78405p-1, 0x1.555654d2bc769p-2,
+ -0x1.00a570d090322p-2, 0x1.e158d823f89cap-3);
+
+ double extra_factor =
+ __llvm_libc::fputil::fma(static_cast<double>(m), LOG_2, LOG_F[fIndex]);
+ switch (FPBits(x).uintval()) {
+ case 0x3f80d19f:
+ return 0x1.a1e82cp-8f;
+ case 0x41178feb:
+ return 0x1.1fcbcep+1f;
+ case 0x4c5d65a5:
+ return 0x1.1e0696p+4f;
+ case 0x65d890d3:
+ return 0x1.a9a3f2p+5f;
+ case 0x6f31a8ec:
+ return 0x1.08b512p+6f;
+ default:
+ return static_cast<float>(__llvm_libc::fputil::fma(d, r, extra_factor));
+ }
+}
+
+#pragma clang diagnostic pop
+
+} // namespace __llvm_libc
diff --git a/libc/src/math/logf.h b/libc/src/math/logf.h
new file mode 100644
index 0000000000000..195580190ba31
--- /dev/null
+++ b/libc/src/math/logf.h
@@ -0,0 +1,18 @@
+//===-- Implementation header for logf --------------------------*- 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_LOGF_H
+#define LLVM_LIBC_SRC_MATH_LOGF_H
+
+namespace __llvm_libc {
+
+float logf(float x);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_MATH_LOGF_H
diff --git a/libc/test/src/math/CMakeLists.txt b/libc/test/src/math/CMakeLists.txt
index 8b1c1467f0e25..e2db5cc7eb7f0 100644
--- a/libc/test/src/math/CMakeLists.txt
+++ b/libc/test/src/math/CMakeLists.txt
@@ -1181,6 +1181,19 @@ add_fp_unittest(
libc.src.__support.FPUtil.fputil
)
+add_fp_unittest(
+ logf_test
+ NEED_MPFR
+ SUITE
+ libc_math_unittests
+ SRCS
+ logf_test.cpp
+ DEPENDS
+ libc.include.math
+ libc.src.math.logf
+ libc.src.__support.FPUtil.fputil
+)
+
add_subdirectory(generic)
add_subdirectory(exhaustive)
add_subdirectory(
diff erential_testing)
diff --git a/libc/test/src/math/
diff erential_testing/CMakeLists.txt b/libc/test/src/math/
diff erential_testing/CMakeLists.txt
index 87fd2dcff2e83..e553bf5bfbef1 100644
--- a/libc/test/src/math/
diff erential_testing/CMakeLists.txt
+++ b/libc/test/src/math/
diff erential_testing/CMakeLists.txt
@@ -227,6 +227,28 @@ add_
diff _binary(
-fno-builtin
)
+add_
diff _binary(
+ logf_
diff
+ SRCS
+ logf_
diff .cpp
+ DEPENDS
+ .single_input_single_output_
diff
+ libc.src.math.logf
+ COMPILE_OPTIONS
+ -fno-builtin
+)
+
+add_
diff _binary(
+ logf_perf
+ SRCS
+ logf_perf.cpp
+ DEPENDS
+ .single_input_single_output_
diff
+ libc.src.math.logf
+ COMPILE_OPTIONS
+ -fno-builtin
+)
+
add_
diff _binary(
logbf_
diff
SRCS
diff --git a/libc/test/src/math/
diff erential_testing/logf_
diff .cpp b/libc/test/src/math/
diff erential_testing/logf_
diff .cpp
new file mode 100644
index 0000000000000..6f5c1ef907e70
--- /dev/null
+++ b/libc/test/src/math/
diff erential_testing/logf_
diff .cpp
@@ -0,0 +1,16 @@
+//===-- Differential test for logf ----------------------------------------===//
+//
+// 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/logf.h"
+
+#include <math.h>
+
+SINGLE_INPUT_SINGLE_OUTPUT_DIFF(float, __llvm_libc::logf, ::logf,
+ "logf_
diff .log")
diff --git a/libc/test/src/math/
diff erential_testing/logf_perf.cpp b/libc/test/src/math/
diff erential_testing/logf_perf.cpp
new file mode 100644
index 0000000000000..ed907ed61048f
--- /dev/null
+++ b/libc/test/src/math/
diff erential_testing/logf_perf.cpp
@@ -0,0 +1,16 @@
+//===-- Differential test for logf ----------------------------------------===//
+//
+// 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/logf.h"
+
+#include <math.h>
+
+SINGLE_INPUT_SINGLE_OUTPUT_PERF(float, __llvm_libc::logf, ::logf,
+ "logf_perf.log")
diff --git a/libc/test/src/math/exhaustive/CMakeLists.txt b/libc/test/src/math/exhaustive/CMakeLists.txt
index 345f6be97950c..51e659114e1d7 100644
--- a/libc/test/src/math/exhaustive/CMakeLists.txt
+++ b/libc/test/src/math/exhaustive/CMakeLists.txt
@@ -51,3 +51,16 @@ add_fp_unittest(
libc.src.math.expm1f
libc.src.__support.FPUtil.fputil
)
+
+add_fp_unittest(
+ logf_test
+ NEED_MPFR
+ SUITE
+ libc_math_exhaustive_tests
+ SRCS
+ logf_test.cpp
+ DEPENDS
+ libc.include.math
+ libc.src.math.logf
+ libc.src.__support.FPUtil.fputil
+)
diff --git a/libc/test/src/math/exhaustive/logf_test.cpp b/libc/test/src/math/exhaustive/logf_test.cpp
new file mode 100644
index 0000000000000..abed0731d8992
--- /dev/null
+++ b/libc/test/src/math/exhaustive/logf_test.cpp
@@ -0,0 +1,26 @@
+//===-- Exhaustive test for logf ------------------------------------------===//
+//
+// 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/logf.h"
+#include "utils/MPFRWrapper/MPFRUtils.h"
+#include "utils/UnitTest/FPMatcher.h"
+#include "utils/UnitTest/Test.h"
+
+using FPBits = __llvm_libc::fputil::FPBits<float>;
+
+namespace mpfr = __llvm_libc::testing::mpfr;
+
+TEST(LlvmLibcLogfExhaustiveTest, AllValues) {
+ uint32_t bits = 0U;
+ do {
+ FPBits xbits(bits);
+ float x = float(xbits);
+ EXPECT_MPFR_MATCH(mpfr::Operation::Log, x, __llvm_libc::logf(x), 0.5);
+ } while (bits++ < 0x7f7f'ffffU);
+}
diff --git a/libc/test/src/math/logf_test.cpp b/libc/test/src/math/logf_test.cpp
new file mode 100644
index 0000000000000..6cee7f74cf0e1
--- /dev/null
+++ b/libc/test/src/math/logf_test.cpp
@@ -0,0 +1,64 @@
+//===-- Unittests for logf-----------------------------------------------===//
+//
+// 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/logf.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(LlvmLibcLogfTest, SpecialNumbers) {
+ EXPECT_FP_EQ(aNaN, __llvm_libc::logf(aNaN));
+ EXPECT_FP_EQ(inf, __llvm_libc::logf(inf));
+ EXPECT_TRUE(isnan(__llvm_libc::logf(neg_inf)));
+ EXPECT_FP_EQ(neg_inf, __llvm_libc::logf(0.0f));
+ EXPECT_FP_EQ(neg_inf, __llvm_libc::logf(-0.0f));
+ EXPECT_TRUE(isnan(__llvm_libc::logf(-1.0f)));
+ EXPECT_FP_EQ(zero, __llvm_libc::logf(1.0f));
+}
+
+TEST(LlvmLibcLogfTest, TrickyInputs) {
+ constexpr int N = 24;
+ constexpr uint32_t INPUTS[N] = {
+ 0x3509dcf6U, 0x3bf86ef0U, 0x3ca1c99fU, 0x3d13e105U, 0x3f7ff1f2U,
+ 0x3f7fffffU, 0x3f800006U, 0x3f800014U, 0x3f80001cU, 0x3f80c777U,
+ 0x3f80ce72U, 0x3f80d19fU, 0x3f80f7bfU, 0x3f80fcfeU, 0x3f81feb4U,
+ 0x3f83d731U, 0x3f90cb1dU, 0x3fc55379U, 0x3fd364d7U, 0x41178febU,
+ 0x4c5d65a5U, 0x4e85f412U, 0x65d890d3U, 0x6f31a8ecU};
+ for (int i = 0; i < N; ++i) {
+ float x = float(FPBits(INPUTS[i]));
+ EXPECT_MPFR_MATCH(mpfr::Operation::Log, x, __llvm_libc::logf(x), 0.5);
+ }
+}
+
+TEST(LlvmLibcLogfTest, 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::logf(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(mpfr::Operation::Log, x, __llvm_libc::logf(x), 0.5);
+ }
+}
diff --git a/libc/utils/MPFRWrapper/MPFRUtils.cpp b/libc/utils/MPFRWrapper/MPFRUtils.cpp
index 366ca02f69e4b..7c4f061b47b50 100644
--- a/libc/utils/MPFRWrapper/MPFRUtils.cpp
+++ b/libc/utils/MPFRWrapper/MPFRUtils.cpp
@@ -165,6 +165,12 @@ class MPFRNumber {
return result;
}
+ MPFRNumber log() const {
+ MPFRNumber result;
+ mpfr_log(result.value, value, MPFR_RNDN);
+ return result;
+ }
+
MPFRNumber remquo(const MPFRNumber &divisor, int "ient) {
MPFRNumber remainder;
long q;
@@ -385,6 +391,8 @@ unaryOperation(Operation op, InputType input) {
return mpfrInput.expm1();
case Operation::Floor:
return mpfrInput.floor();
+ case Operation::Log:
+ return mpfrInput.log();
case Operation::Mod2PI:
return mpfrInput.mod_2pi();
case Operation::ModPIOver2:
diff --git a/libc/utils/MPFRWrapper/MPFRUtils.h b/libc/utils/MPFRWrapper/MPFRUtils.h
index d2ca7612cf563..ff35a56231bb1 100644
--- a/libc/utils/MPFRWrapper/MPFRUtils.h
+++ b/libc/utils/MPFRWrapper/MPFRUtils.h
@@ -30,6 +30,7 @@ enum class Operation : int {
Exp2,
Expm1,
Floor,
+ Log,
Mod2PI,
ModPIOver2,
ModPIOver4,
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