[libc-commits] [libc] 64721a3 - [libc] Implement exp2f function that is correctly rounded for all rounding modes.
Tue Ly via libc-commits
libc-commits at lists.llvm.org
Mon Mar 14 06:42:57 PDT 2022
Author: Tue Ly
Date: 2022-03-14T09:42:37-04:00
New Revision: 64721a3312c6e1b7189ffdcf05f9c6ee5b7e6777
URL: https://github.com/llvm/llvm-project/commit/64721a3312c6e1b7189ffdcf05f9c6ee5b7e6777
DIFF: https://github.com/llvm/llvm-project/commit/64721a3312c6e1b7189ffdcf05f9c6ee5b7e6777.diff
LOG: [libc] Implement exp2f function that is correctly rounded for all rounding modes.
Implement exp2f function that is correctly rounded for all rounding modes.
Reviewed By: sivachandra, zimmermann6
Differential Revision: https://reviews.llvm.org/D121463
Added:
libc/test/src/math/exhaustive/exp2f_test.cpp
Modified:
libc/src/math/generic/CMakeLists.txt
libc/src/math/generic/exp2f.cpp
libc/test/src/math/exhaustive/CMakeLists.txt
libc/test/src/math/exp2f_test.cpp
Removed:
################################################################################
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index e7449bdf1753d..e925e012f18e8 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -489,9 +489,10 @@ add_entrypoint_object(
HDRS
../exp2f.h
DEPENDS
- .exp_utils
- .math_utils
+ libc.src.__support.FPUtil.fputil
libc.include.math
+ COMPILE_OPTIONS
+ -O3
)
add_entrypoint_object(
diff --git a/libc/src/math/generic/exp2f.cpp b/libc/src/math/generic/exp2f.cpp
index f9cf8d81df207..b19cf8ebbd060 100644
--- a/libc/src/math/generic/exp2f.cpp
+++ b/libc/src/math/generic/exp2f.cpp
@@ -7,58 +7,159 @@
//===----------------------------------------------------------------------===//
#include "src/math/exp2f.h"
-#include "exp_utils.h"
-#include "math_utils.h"
-
+#include "src/__support/FPUtil/BasicOperations.h"
+#include "src/__support/FPUtil/FEnvImpl.h"
+#include "src/__support/FPUtil/FMA.h"
+#include "src/__support/FPUtil/FPBits.h"
+#include "src/__support/FPUtil/PolyEval.h"
#include "src/__support/common.h"
-#include <math.h>
-
-#include <stdint.h>
-#define T exp2f_data.tab
-#define C exp2f_data.poly
-#define SHIFT exp2f_data.shift_scaled
+#include <errno.h>
namespace __llvm_libc {
+// Lookup table for 2^(m * 2^(-7)) with m = 0, ..., 127.
+// Table is generated with Sollya as follow:
+// > display = hexadecimal;
+// > for i from 0 to 127 do { D(2^(i / 128)); };
+static constexpr double EXP_M[128] = {
+ 0x1.0000000000000p0, 0x1.0163da9fb3335p0, 0x1.02c9a3e778061p0,
+ 0x1.04315e86e7f85p0, 0x1.059b0d3158574p0, 0x1.0706b29ddf6dep0,
+ 0x1.0874518759bc8p0, 0x1.09e3ecac6f383p0, 0x1.0b5586cf9890fp0,
+ 0x1.0cc922b7247f7p0, 0x1.0e3ec32d3d1a2p0, 0x1.0fb66affed31bp0,
+ 0x1.11301d0125b51p0, 0x1.12abdc06c31ccp0, 0x1.1429aaea92de0p0,
+ 0x1.15a98c8a58e51p0, 0x1.172b83c7d517bp0, 0x1.18af9388c8deap0,
+ 0x1.1a35beb6fcb75p0, 0x1.1bbe084045cd4p0, 0x1.1d4873168b9aap0,
+ 0x1.1ed5022fcd91dp0, 0x1.2063b88628cd6p0, 0x1.21f49917ddc96p0,
+ 0x1.2387a6e756238p0, 0x1.251ce4fb2a63fp0, 0x1.26b4565e27cddp0,
+ 0x1.284dfe1f56381p0, 0x1.29e9df51fdee1p0, 0x1.2b87fd0dad990p0,
+ 0x1.2d285a6e4030bp0, 0x1.2ecafa93e2f56p0, 0x1.306fe0a31b715p0,
+ 0x1.32170fc4cd831p0, 0x1.33c08b26416ffp0, 0x1.356c55f929ff1p0,
+ 0x1.371a7373aa9cbp0, 0x1.38cae6d05d866p0, 0x1.3a7db34e59ff7p0,
+ 0x1.3c32dc313a8e5p0, 0x1.3dea64c123422p0, 0x1.3fa4504ac801cp0,
+ 0x1.4160a21f72e2ap0, 0x1.431f5d950a897p0, 0x1.44e086061892dp0,
+ 0x1.46a41ed1d0057p0, 0x1.486a2b5c13cd0p0, 0x1.4a32af0d7d3dep0,
+ 0x1.4bfdad5362a27p0, 0x1.4dcb299fddd0dp0, 0x1.4f9b2769d2ca7p0,
+ 0x1.516daa2cf6642p0, 0x1.5342b569d4f82p0, 0x1.551a4ca5d920fp0,
+ 0x1.56f4736b527dap0, 0x1.58d12d497c7fdp0, 0x1.5ab07dd485429p0,
+ 0x1.5c9268a5946b7p0, 0x1.5e76f15ad2148p0, 0x1.605e1b976dc09p0,
+ 0x1.6247eb03a5585p0, 0x1.6434634ccc320p0, 0x1.6623882552225p0,
+ 0x1.68155d44ca973p0, 0x1.6a09e667f3bcdp0, 0x1.6c012750bdabfp0,
+ 0x1.6dfb23c651a2fp0, 0x1.6ff7df9519484p0, 0x1.71f75e8ec5f74p0,
+ 0x1.73f9a48a58174p0, 0x1.75feb564267c9p0, 0x1.780694fde5d3fp0,
+ 0x1.7a11473eb0187p0, 0x1.7c1ed0130c132p0, 0x1.7e2f336cf4e62p0,
+ 0x1.80427543e1a12p0, 0x1.82589994cce13p0, 0x1.8471a4623c7adp0,
+ 0x1.868d99b4492edp0, 0x1.88ac7d98a6699p0, 0x1.8ace5422aa0dbp0,
+ 0x1.8cf3216b5448cp0, 0x1.8f1ae99157736p0, 0x1.9145b0b91ffc6p0,
+ 0x1.93737b0cdc5e5p0, 0x1.95a44cbc8520fp0, 0x1.97d829fde4e50p0,
+ 0x1.9a0f170ca07bap0, 0x1.9c49182a3f090p0, 0x1.9e86319e32323p0,
+ 0x1.a0c667b5de565p0, 0x1.a309bec4a2d33p0, 0x1.a5503b23e255dp0,
+ 0x1.a799e1330b358p0, 0x1.a9e6b5579fdbfp0, 0x1.ac36bbfd3f37ap0,
+ 0x1.ae89f995ad3adp0, 0x1.b0e07298db666p0, 0x1.b33a2b84f15fbp0,
+ 0x1.b59728de5593ap0, 0x1.b7f76f2fb5e47p0, 0x1.ba5b030a1064ap0,
+ 0x1.bcc1e904bc1d2p0, 0x1.bf2c25bd71e09p0, 0x1.c199bdd85529cp0,
+ 0x1.c40ab5fffd07ap0, 0x1.c67f12e57d14bp0, 0x1.c8f6d9406e7b5p0,
+ 0x1.cb720dcef9069p0, 0x1.cdf0b555dc3fap0, 0x1.d072d4a07897cp0,
+ 0x1.d2f87080d89f2p0, 0x1.d5818dcfba487p0, 0x1.d80e316c98398p0,
+ 0x1.da9e603db3285p0, 0x1.dd321f301b460p0, 0x1.dfc97337b9b5fp0,
+ 0x1.e264614f5a129p0, 0x1.e502ee78b3ff6p0, 0x1.e7a51fbc74c83p0,
+ 0x1.ea4afa2a490dap0, 0x1.ecf482d8e67f1p0, 0x1.efa1bee615a27p0,
+ 0x1.f252b376bba97p0, 0x1.f50765b6e4540p0, 0x1.f7bfdad9cbe14p0,
+ 0x1.fa7c1819e90d8p0, 0x1.fd3c22b8f71f1p0,
+};
+
+INLINE_FMA
LLVM_LIBC_FUNCTION(float, exp2f, (float x)) {
- uint32_t abstop;
- uint64_t ki, t;
- // double_t for better performance on targets with FLT_EVAL_METHOD==2.
- double_t kd, xd, z, r, r2, y, s;
+ using FPBits = typename fputil::FPBits<float>;
+ FPBits xbits(x);
- xd = static_cast<double_t>(x);
- abstop = top12_bits(x) & 0x7ff;
- if (unlikely(abstop >= top12_bits(128.0f))) {
- // |x| >= 128 or x is nan.
- if (as_uint32_bits(x) == as_uint32_bits(-INFINITY))
+ // When x < -150 or nan
+ if (unlikely(xbits.uintval() > 0xc316'0000U)) {
+ // exp(-Inf) = 0
+ if (xbits.is_inf())
return 0.0f;
- if (abstop >= top12_bits(INFINITY))
- return x + x;
- if (x > 0.0f)
- return overflow<float>(0);
- if (x <= -150.0f)
- return underflow<float>(0);
- if (x < -149.0f)
- return may_underflow<float>(0);
+ // exp(nan) = nan
+ if (xbits.is_nan())
+ return x;
+ if (fputil::get_round() == FE_UPWARD)
+ return static_cast<float>(FPBits(FPBits::MIN_SUBNORMAL));
+ if (x != 0.0f)
+ errno = ERANGE;
+ return 0.0f;
}
+ // x >= 128 or nan
+ if (unlikely(!xbits.get_sign() && (xbits.uintval() >= 0x4300'0000U))) {
+ if (xbits.uintval() < 0x7f80'0000U) {
+ int rounding = fputil::get_round();
+ if (rounding == FE_DOWNWARD || rounding == FE_TOWARDZERO)
+ return static_cast<float>(FPBits(FPBits::MAX_NORMAL));
- // x = k/N + r with r in [-1/(2N), 1/(2N)] and int k.
- kd = static_cast<double>(xd + SHIFT);
- ki = as_uint64_bits(kd);
- kd -= SHIFT; // k/N for int k.
- r = xd - kd;
+ errno = ERANGE;
+ }
+ return x + static_cast<float>(FPBits::inf());
+ }
+ // |x| < 2^-25
+ if (unlikely(xbits.get_unbiased_exponent() <= 101)) {
+ return 1.0f + x;
+ }
+ // Exceptional values.
+ switch (xbits.uintval()) {
+ case 0x3b42'9d37U: // x = 0x1.853a6ep-9f
+ if (fputil::get_round() == FE_TONEAREST)
+ return 0x1.00870ap+0f;
+ break;
+ case 0xbcf3'a937U: // x = -0x1.e7526ep-6f
+ if (fputil::get_round() == FE_TONEAREST)
+ return 0x1.f58d62p-1f;
+ break;
+ }
+
+ // For -150 <= x < 128, to compute 2^x, we perform the following range
+ // reduction: find hi, mid, lo such that:
+ // x = hi + mid + lo, in which
+ // hi is an integer,
+ // mid * 2^7 is an integer
+ // -2^(-8) <= lo < 2^-8.
+ // In particular,
+ // hi + mid = round(x * 2^7) * 2^(-7).
+ // Then,
+ // 2^(x) = 2^(hi + mid + lo) = 2^hi * 2^mid * 2^lo.
+ // Multiply by 2^hi is simply adding hi to the exponent field. We store
+ // exp(mid) in the lookup tables EXP_M. exp(lo) is computed using a degree-7
+ // minimax polynomial generated by Sollya.
- // exp2(x) = 2^(k/N) * 2^r ~= s * (C0*r^3 + C1*r^2 + C2*r + 1)
- t = T[ki % N];
- t += ki << (52 - EXP2F_TABLE_BITS);
- s = as_double(t);
- z = C[0] * r + C[1];
- r2 = r * r;
- y = C[2] * r + 1;
- y = z * r2 + y;
- y = y * s;
- return static_cast<float>(y);
+ // x_hi = hi + mid.
+ int x_hi = static_cast<int>(x * 0x1.0p7f);
+ // Subtract (hi + mid) from x to get lo.
+ x -= static_cast<float>(x_hi) * 0x1.0p-7f;
+ double xd = static_cast<double>(x);
+ // Make sure that -2^(-8) <= lo < 2^-8.
+ if (x >= 0x1.0p-8f) {
+ ++x_hi;
+ xd -= 0x1.0p-7;
+ }
+ if (x < -0x1.0p-8f) {
+ --x_hi;
+ xd += 0x1.0p-7;
+ }
+ // For 2-complement integers, arithmetic right shift is the same as dividing
+ // by a power of 2 and then round down (toward negative infinity).
+ int hi = x_hi >> 7;
+ // mid = x_hi & 0x0000'007fU;
+ double exp_mid = EXP_M[x_hi & 0x7f];
+ // Degree-6 minimax polynomial generated by Sollya with the following
+ // commands:
+ // > display = hexadecimal;
+ // > Q = fpminimax((2^x - 1)/x, 5, [|D...|], [-2^-8, 2^-8]);
+ // > Q;
+ double exp_lo =
+ fputil::polyeval(xd, 0x1p0, 0x1.62e42fefa39efp-1, 0x1.ebfbdff82c58ep-3,
+ 0x1.c6b08d711fe2fp-5, 0x1.3b2ab6fe3deb5p-7,
+ 0x1.5d72a05f45c04p-10, 0x1.4284d40c33326p-13);
+ fputil::FPBits<double> result(exp_mid * exp_lo);
+ result.set_unbiased_exponent(static_cast<uint16_t>(
+ static_cast<int>(result.get_unbiased_exponent()) + hi));
+ return static_cast<float>(static_cast<double>(result));
}
} // namespace __llvm_libc
diff --git a/libc/test/src/math/exhaustive/CMakeLists.txt b/libc/test/src/math/exhaustive/CMakeLists.txt
index 01ffc79dde215..c4ee2bb12315c 100644
--- a/libc/test/src/math/exhaustive/CMakeLists.txt
+++ b/libc/test/src/math/exhaustive/CMakeLists.txt
@@ -64,6 +64,23 @@ add_fp_unittest(
-lpthread
)
+add_fp_unittest(
+ exp2f_test
+ NO_RUN_POSTBUILD
+ NEED_MPFR
+ SUITE
+ libc_math_exhaustive_tests
+ SRCS
+ exp2f_test.cpp
+ DEPENDS
+ .exhaustive_test
+ libc.include.math
+ libc.src.math.exp2f
+ libc.src.__support.FPUtil.fputil
+ LINK_OPTIONS
+ -lpthread
+)
+
add_fp_unittest(
expm1f_test
NEED_MPFR
diff --git a/libc/test/src/math/exhaustive/exp2f_test.cpp b/libc/test/src/math/exhaustive/exp2f_test.cpp
new file mode 100644
index 0000000000000..48fa434ff332b
--- /dev/null
+++ b/libc/test/src/math/exhaustive/exp2f_test.cpp
@@ -0,0 +1,79 @@
+//===-- Exhaustive test for exp2f -----------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "exhaustive_test.h"
+#include "src/__support/FPUtil/FPBits.h"
+#include "src/math/exp2f.h"
+#include "utils/MPFRWrapper/MPFRUtils.h"
+#include "utils/UnitTest/FPMatcher.h"
+
+using FPBits = __llvm_libc::fputil::FPBits<float>;
+
+namespace mpfr = __llvm_libc::testing::mpfr;
+
+struct LlvmLibcExp2fExhaustiveTest : public LlvmLibcExhaustiveTest<uint32_t> {
+ void check(uint32_t start, uint32_t stop,
+ mpfr::RoundingMode rounding) override {
+ mpfr::ForceRoundingMode r(rounding);
+ uint32_t bits = start;
+ do {
+ FPBits xbits(bits);
+ float x = float(xbits);
+ EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), 0.5,
+ rounding);
+ } while (bits++ < stop);
+ }
+};
+
+static constexpr int NUM_THREADS = 16;
+
+// Range: [0, 128];
+static constexpr uint32_t POS_START = 0x0000'0000U;
+static constexpr uint32_t POS_STOP = 0x4300'0000U;
+
+TEST_F(LlvmLibcExp2fExhaustiveTest, PostiveRangeRoundNearestTieToEven) {
+ test_full_range(POS_START, POS_STOP, NUM_THREADS,
+ mpfr::RoundingMode::Nearest);
+}
+
+TEST_F(LlvmLibcExp2fExhaustiveTest, PostiveRangeRoundUp) {
+ test_full_range(POS_START, POS_STOP, NUM_THREADS, mpfr::RoundingMode::Upward);
+}
+
+TEST_F(LlvmLibcExp2fExhaustiveTest, PostiveRangeRoundDown) {
+ test_full_range(POS_START, POS_STOP, NUM_THREADS,
+ mpfr::RoundingMode::Downward);
+}
+
+TEST_F(LlvmLibcExp2fExhaustiveTest, PostiveRangeRoundTowardZero) {
+ test_full_range(POS_START, POS_STOP, NUM_THREADS,
+ mpfr::RoundingMode::TowardZero);
+}
+
+// Range: [-150, 0];
+static constexpr uint32_t NEG_START = 0x8000'0000U;
+static constexpr uint32_t NEG_STOP = 0xc316'0000U;
+
+TEST_F(LlvmLibcExp2fExhaustiveTest, NegativeRangeRoundNearestTieToEven) {
+ test_full_range(NEG_START, NEG_STOP, NUM_THREADS,
+ mpfr::RoundingMode::Nearest);
+}
+
+TEST_F(LlvmLibcExp2fExhaustiveTest, NegativeRangeRoundUp) {
+ test_full_range(NEG_START, NEG_STOP, NUM_THREADS, mpfr::RoundingMode::Upward);
+}
+
+TEST_F(LlvmLibcExp2fExhaustiveTest, NegativeRangeRoundDown) {
+ test_full_range(NEG_START, NEG_STOP, NUM_THREADS,
+ mpfr::RoundingMode::Downward);
+}
+
+TEST_F(LlvmLibcExp2fExhaustiveTest, NegativeRangeRoundTowardZero) {
+ test_full_range(NEG_START, NEG_STOP, NUM_THREADS,
+ mpfr::RoundingMode::TowardZero);
+}
diff --git a/libc/test/src/math/exp2f_test.cpp b/libc/test/src/math/exp2f_test.cpp
index 4cc73830f7d51..20c22c6bbb9e5 100644
--- a/libc/test/src/math/exp2f_test.cpp
+++ b/libc/test/src/math/exp2f_test.cpp
@@ -39,7 +39,7 @@ TEST(LlvmLibcExp2fTest, SpecialNumbers) {
EXPECT_MATH_ERRNO(0);
}
-TEST(LlvmLibcExpfTest, Overflow) {
+TEST(LlvmLibcExp2fTest, Overflow) {
errno = 0;
EXPECT_FP_EQ(inf, __llvm_libc::exp2f(float(FPBits(0x7f7fffffU))));
EXPECT_MATH_ERRNO(ERANGE);
@@ -53,50 +53,73 @@ TEST(LlvmLibcExpfTest, Overflow) {
// Test with inputs which are the borders of underflow/overflow but still
// produce valid results without setting errno.
-TEST(LlvmLibcExpfTest, Borderline) {
+TEST(LlvmLibcExp2fTest, Borderline) {
float x;
errno = 0;
x = float(FPBits(0x42fa0001U));
- EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), 1.0);
+ EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Exp2, x,
+ __llvm_libc::exp2f(x), 0.5);
EXPECT_MATH_ERRNO(0);
x = float(FPBits(0x42ffffffU));
- EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), 1.0);
+ EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Exp2, x,
+ __llvm_libc::exp2f(x), 0.5);
EXPECT_MATH_ERRNO(0);
x = float(FPBits(0xc2fa0001U));
- EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), 1.0);
+ EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Exp2, x,
+ __llvm_libc::exp2f(x), 0.5);
EXPECT_MATH_ERRNO(0);
x = float(FPBits(0xc2fc0000U));
- EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), 1.0);
+ EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Exp2, x,
+ __llvm_libc::exp2f(x), 0.5);
EXPECT_MATH_ERRNO(0);
x = float(FPBits(0xc2fc0001U));
- EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), 1.0);
+ EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Exp2, x,
+ __llvm_libc::exp2f(x), 0.5);
EXPECT_MATH_ERRNO(0);
x = float(FPBits(0xc3150000U));
- EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), 1.0);
+ EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Exp2, x,
+ __llvm_libc::exp2f(x), 0.5);
+ EXPECT_MATH_ERRNO(0);
+
+ x = float(FPBits(0x3b42'9d37U));
+ EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Exp2, x,
+ __llvm_libc::exp2f(x), 0.5);
+ EXPECT_MATH_ERRNO(0);
+
+ x = float(FPBits(0xbcf3'a937U));
+ EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Exp2, x,
+ __llvm_libc::exp2f(x), 0.5);
EXPECT_MATH_ERRNO(0);
}
-TEST(LlvmLibcExpfTest, Underflow) {
+TEST(LlvmLibcExp2fTest, Underflow) {
errno = 0;
EXPECT_FP_EQ(0.0f, __llvm_libc::exp2f(float(FPBits(0xff7fffffU))));
EXPECT_MATH_ERRNO(ERANGE);
float x = float(FPBits(0xc3158000U));
- EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), 1.0);
+ EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Exp2, x,
+ __llvm_libc::exp2f(x), 0.5);
+ EXPECT_MATH_ERRNO(0);
+
+ x = float(FPBits(0xc3160000U));
+ EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Exp2, x,
+ __llvm_libc::exp2f(x), 0.5);
EXPECT_MATH_ERRNO(ERANGE);
x = float(FPBits(0xc3165432U));
- EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), 1.0);
+ EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Exp2, x,
+ __llvm_libc::exp2f(x), 0.5);
EXPECT_MATH_ERRNO(ERANGE);
}
-TEST(LlvmLibcexp2fTest, InFloatRange) {
+TEST(LlvmLibcExp2fTest, 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) {
@@ -112,6 +135,7 @@ TEST(LlvmLibcexp2fTest, InFloatRange) {
// wider precision.
if (isnan(result) || isinf(result) || errno != 0)
continue;
- ASSERT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), 1.0);
+ ASSERT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Exp2, x,
+ __llvm_libc::exp2f(x), 0.5);
}
}
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