[libc][math] Implement nexttoward functions #72763
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@llvm/pr-subscribers-libc Author: Nishant Mittal (nishantwrp) ChangesImplements the cc: @lntue Patch is 27.50 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/72763.diff 23 Files Affected:
diff --git a/libc/config/darwin/arm/entrypoints.txt b/libc/config/darwin/arm/entrypoints.txt
index 362138c92a6869f..da4a2345f389c49 100644
--- a/libc/config/darwin/arm/entrypoints.txt
+++ b/libc/config/darwin/arm/entrypoints.txt
@@ -199,6 +199,9 @@ set(TARGET_LIBM_ENTRYPOINTS
libc.src.math.nextafter
libc.src.math.nextafterf
libc.src.math.nextafterl
+ libc.src.math.nexttoward
+ libc.src.math.nexttowardf
+ libc.src.math.nexttowardl
libc.src.math.powf
libc.src.math.remainderf
libc.src.math.remainder
diff --git a/libc/config/darwin/x86_64/entrypoints.txt b/libc/config/darwin/x86_64/entrypoints.txt
index 57d21a2ce273574..e29e75ec92dadcd 100644
--- a/libc/config/darwin/x86_64/entrypoints.txt
+++ b/libc/config/darwin/x86_64/entrypoints.txt
@@ -178,6 +178,9 @@ set(TARGET_LIBM_ENTRYPOINTS
#libc.src.math.nextafter
#libc.src.math.nextafterf
#libc.src.math.nextafterl
+ #libc.src.math.nexttoward
+ #libc.src.math.nexttowardf
+ #libc.src.math.nexttowardl
#libc.src.math.remainderf
#libc.src.math.remainder
#libc.src.math.remainderl
diff --git a/libc/config/gpu/entrypoints.txt b/libc/config/gpu/entrypoints.txt
index 5dda6aa71d36f81..ba86e31ee0adcd1 100644
--- a/libc/config/gpu/entrypoints.txt
+++ b/libc/config/gpu/entrypoints.txt
@@ -219,6 +219,8 @@ set(TARGET_LIBM_ENTRYPOINTS
libc.src.math.nearbyintf
libc.src.math.nextafter
libc.src.math.nextafterf
+ libc.src.math.nexttoward
+ libc.src.math.nexttowardf
libc.src.math.pow
libc.src.math.powf
libc.src.math.remainder
diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index 096e2afb06e5a9d..284feb7b99096ec 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -316,6 +316,9 @@ set(TARGET_LIBM_ENTRYPOINTS
libc.src.math.nextafter
libc.src.math.nextafterf
libc.src.math.nextafterl
+ libc.src.math.nexttoward
+ libc.src.math.nexttowardf
+ libc.src.math.nexttowardl
libc.src.math.powf
libc.src.math.remainderf
libc.src.math.remainder
diff --git a/libc/config/linux/riscv/entrypoints.txt b/libc/config/linux/riscv/entrypoints.txt
index 7dadbc7f8285477..a5f0c91e32d0810 100644
--- a/libc/config/linux/riscv/entrypoints.txt
+++ b/libc/config/linux/riscv/entrypoints.txt
@@ -325,6 +325,9 @@ set(TARGET_LIBM_ENTRYPOINTS
libc.src.math.nextafter
libc.src.math.nextafterf
libc.src.math.nextafterl
+ libc.src.math.nexttoward
+ libc.src.math.nexttowardf
+ libc.src.math.nexttowardl
libc.src.math.powf
libc.src.math.remainderf
libc.src.math.remainder
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 83bc8461999ed66..63aa7473115a08e 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -329,6 +329,9 @@ set(TARGET_LIBM_ENTRYPOINTS
libc.src.math.nextafter
libc.src.math.nextafterf
libc.src.math.nextafterl
+ libc.src.math.nexttoward
+ libc.src.math.nexttowardf
+ libc.src.math.nexttowardl
libc.src.math.powf
libc.src.math.remainderf
libc.src.math.remainder
diff --git a/libc/config/windows/entrypoints.txt b/libc/config/windows/entrypoints.txt
index 5611b399e8bca8b..4c0a6ec37fe4cc2 100644
--- a/libc/config/windows/entrypoints.txt
+++ b/libc/config/windows/entrypoints.txt
@@ -198,6 +198,9 @@ set(TARGET_LIBM_ENTRYPOINTS
libc.src.math.nextafter
libc.src.math.nextafterf
libc.src.math.nextafterl
+ libc.src.math.nexttoward
+ libc.src.math.nexttowardf
+ libc.src.math.nexttowardl
libc.src.math.powf
libc.src.math.remainderf
libc.src.math.remainder
diff --git a/libc/spec/stdc.td b/libc/spec/stdc.td
index 4e38cb742d2844e..58c95b856535a12 100644
--- a/libc/spec/stdc.td
+++ b/libc/spec/stdc.td
@@ -492,6 +492,10 @@ def StdC : StandardSpec<"stdc"> {
FunctionSpec<"nextafter", RetValSpec<DoubleType>, [ArgSpec<DoubleType>, ArgSpec<DoubleType>]>,
FunctionSpec<"nextafterl", RetValSpec<LongDoubleType>, [ArgSpec<LongDoubleType>, ArgSpec<LongDoubleType>]>,
+ FunctionSpec<"nexttowardf", RetValSpec<FloatType>, [ArgSpec<FloatType>, ArgSpec<LongDoubleType>]>,
+ FunctionSpec<"nexttoward", RetValSpec<DoubleType>, [ArgSpec<DoubleType>, ArgSpec<LongDoubleType>]>,
+ FunctionSpec<"nexttowardl", RetValSpec<LongDoubleType>, [ArgSpec<LongDoubleType>, ArgSpec<LongDoubleType>]>,
+
FunctionSpec<"powf", RetValSpec<FloatType>, [ArgSpec<FloatType>, ArgSpec<FloatType>]>,
FunctionSpec<"pow", RetValSpec<DoubleType>, [ArgSpec<DoubleType>, ArgSpec<DoubleType>]>,
diff --git a/libc/src/__support/FPUtil/ManipulationFunctions.h b/libc/src/__support/FPUtil/ManipulationFunctions.h
index 6d62a2d0fcdf2be..ff131195528ddb0 100644
--- a/libc/src/__support/FPUtil/ManipulationFunctions.h
+++ b/libc/src/__support/FPUtil/ManipulationFunctions.h
@@ -10,6 +10,7 @@
#define LLVM_LIBC_SRC___SUPPORT_FPUTIL_MANIPULATIONFUNCTIONS_H
#include "FPBits.h"
+#include "FloatProperties.h"
#include "NearestIntegerOperations.h"
#include "NormalFloat.h"
#include "PlatformDefs.h"
@@ -19,6 +20,7 @@
#include "src/__support/macros/attributes.h"
#include "src/__support/macros/optimization.h" // LIBC_UNLIKELY
+#include <fenv.h>
#include <limits.h>
#include <math.h>
@@ -169,8 +171,49 @@ LIBC_INLINE T nextafter(T from, T to) {
int_val = (to_bits.uintval() & sign_mask) + UIntType(1);
}
+ UIntType exponent_bits = int_val & FloatProperties<T>::EXPONENT_MASK;
+ if (exponent_bits == UIntType(0))
+ raise_except_if_required(FE_UNDERFLOW | FE_INEXACT);
+ else if (exponent_bits == FloatProperties<T>::EXPONENT_MASK)
+ raise_except_if_required(FE_OVERFLOW | FE_INEXACT);
+
+ return cpp::bit_cast<T>(int_val);
+}
+
+template <typename T, cpp::enable_if_t<cpp::is_floating_point_v<T>, int> = 0>
+LIBC_INLINE T nexttoward(T from, long double to) {
+ FPBits<T> from_bits(from);
+ if (from_bits.is_nan())
+ return from;
+
+ FPBits<long double> to_bits(to);
+ if (to_bits.is_nan())
+ return to;
+
+ if ((long double)from == to)
+ return to;
+
+ using UIntType = typename FPBits<T>::UIntType;
+ UIntType int_val = from_bits.uintval();
+ if (from != T(0.0)) {
+ if ((from < to) == (from > T(0.0))) {
+ ++int_val;
+ } else {
+ --int_val;
+ }
+ } else {
+ int_val = FPBits<T>::MIN_SUBNORMAL;
+ if (to_bits.get_sign())
+ int_val |= FloatProperties<T>::SIGN_MASK;
+ }
+
+ UIntType exponent_bits = int_val & FloatProperties<T>::EXPONENT_MASK;
+ if (exponent_bits == UIntType(0))
+ raise_except_if_required(FE_UNDERFLOW | FE_INEXACT);
+ else if (exponent_bits == FloatProperties<T>::EXPONENT_MASK)
+ raise_except_if_required(FE_OVERFLOW | FE_INEXACT);
+
return cpp::bit_cast<T>(int_val);
- // TODO: Raise floating point exceptions as required by the standard.
}
} // namespace fputil
diff --git a/libc/src/__support/FPUtil/x86_64/NextAfterLongDouble.h b/libc/src/__support/FPUtil/x86_64/NextAfterLongDouble.h
index 52ef2568c1dce06..354739bab1b1998 100644
--- a/libc/src/__support/FPUtil/x86_64/NextAfterLongDouble.h
+++ b/libc/src/__support/FPUtil/x86_64/NextAfterLongDouble.h
@@ -59,6 +59,8 @@ LIBC_INLINE long double nextafter(long double from, long double to) {
// which is what is expected. Since NaNs are handling separately,
// it will never overflow "beyond" infinity.
from_bits.set_unbiased_exponent(from_bits.get_unbiased_exponent() + 1);
+ if (from_bits.is_inf())
+ raise_except_if_required(FE_OVERFLOW | FE_INEXACT);
return from_bits;
} else {
++int_val;
@@ -105,6 +107,8 @@ LIBC_INLINE long double nextafter(long double from, long double to) {
// which is what is expected. Since NaNs are handling separately,
// it will never overflow "beyond" infinity.
from_bits.set_unbiased_exponent(from_bits.get_unbiased_exponent() + 1);
+ if (from_bits.is_inf())
+ raise_except_if_required(FE_OVERFLOW | FE_INEXACT);
return from_bits;
} else {
++int_val;
@@ -112,8 +116,12 @@ LIBC_INLINE long double nextafter(long double from, long double to) {
}
}
+ UIntType implicit_bit =
+ int_val & (UIntType(1) << MantissaWidth<long double>::VALUE);
+ if (implicit_bit == UIntType(0))
+ raise_except_if_required(FE_UNDERFLOW | FE_INEXACT);
+
return cpp::bit_cast<long double>(int_val);
- // TODO: Raise floating point exceptions as required by the standard.
}
} // namespace fputil
diff --git a/libc/src/math/CMakeLists.txt b/libc/src/math/CMakeLists.txt
index 4aea54c7a457547..ffabc27bc00abc7 100644
--- a/libc/src/math/CMakeLists.txt
+++ b/libc/src/math/CMakeLists.txt
@@ -187,6 +187,10 @@ add_math_entrypoint_object(nextafter)
add_math_entrypoint_object(nextafterf)
add_math_entrypoint_object(nextafterl)
+add_math_entrypoint_object(nexttoward)
+add_math_entrypoint_object(nexttowardf)
+add_math_entrypoint_object(nexttowardl)
+
add_math_entrypoint_object(pow)
add_math_entrypoint_object(powf)
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index 7ac365f55bb6f83..da59e74a8e822a8 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -1474,6 +1474,42 @@ add_entrypoint_object(
-O2
)
+add_entrypoint_object(
+ nexttoward
+ SRCS
+ nexttoward.cpp
+ HDRS
+ ../nexttoward.h
+ DEPENDS
+ libc.src.__support.FPUtil.manipulation_functions
+ COMPILE_OPTIONS
+ -O2
+)
+
+add_entrypoint_object(
+ nexttowardf
+ SRCS
+ nexttowardf.cpp
+ HDRS
+ ../nexttowardf.h
+ DEPENDS
+ libc.src.__support.FPUtil.manipulation_functions
+ COMPILE_OPTIONS
+ -O2
+)
+
+add_entrypoint_object(
+ nexttowardl
+ SRCS
+ nexttowardl.cpp
+ HDRS
+ ../nexttowardl.h
+ DEPENDS
+ libc.src.__support.FPUtil.manipulation_functions
+ COMPILE_OPTIONS
+ -O2
+)
+
add_entrypoint_object(
fmod
SRCS
diff --git a/libc/src/math/generic/nexttoward.cpp b/libc/src/math/generic/nexttoward.cpp
new file mode 100644
index 000000000000000..38b45d6d2f65d9c
--- /dev/null
+++ b/libc/src/math/generic/nexttoward.cpp
@@ -0,0 +1,19 @@
+//===-- Implementation of nexttoward 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/nexttoward.h"
+#include "src/__support/FPUtil/ManipulationFunctions.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(double, nexttoward, (double x, long double y)) {
+ return fputil::nexttoward(x, y);
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/src/math/generic/nexttowardf.cpp b/libc/src/math/generic/nexttowardf.cpp
new file mode 100644
index 000000000000000..59a9f805a6946a1
--- /dev/null
+++ b/libc/src/math/generic/nexttowardf.cpp
@@ -0,0 +1,19 @@
+//===-- Implementation of nexttowardf 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/nexttowardf.h"
+#include "src/__support/FPUtil/ManipulationFunctions.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(float, nexttowardf, (float x, long double y)) {
+ return fputil::nexttoward(x, y);
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/src/math/generic/nexttowardl.cpp b/libc/src/math/generic/nexttowardl.cpp
new file mode 100644
index 000000000000000..0c887ae0671bc98
--- /dev/null
+++ b/libc/src/math/generic/nexttowardl.cpp
@@ -0,0 +1,22 @@
+//===-- Implementation of nexttowardl 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/nexttowardl.h"
+#include "src/__support/FPUtil/ManipulationFunctions.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(long double, nexttowardl, (long double x, long double y)) {
+ // We can reuse the nextafter implementation because nexttoward behaves
+ // exactly same as nextafter in case of long doubles. Also, we have explcitly
+ // handled the special 80-bit long doubles in nextafter implementation.
+ return fputil::nextafter(x, y);
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/src/math/nexttoward.h b/libc/src/math/nexttoward.h
new file mode 100644
index 000000000000000..6a5bece9957689c
--- /dev/null
+++ b/libc/src/math/nexttoward.h
@@ -0,0 +1,18 @@
+//===-- Implementation header for nexttoward --------------------*- 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_NEXTTOWARD_H
+#define LLVM_LIBC_SRC_MATH_NEXTTOWARD_H
+
+namespace LIBC_NAMESPACE {
+
+double nexttoward(double x, long double y);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_MATH_NEXTTOWARD_H
diff --git a/libc/src/math/nexttowardf.h b/libc/src/math/nexttowardf.h
new file mode 100644
index 000000000000000..7a0eb2a61b4d4b2
--- /dev/null
+++ b/libc/src/math/nexttowardf.h
@@ -0,0 +1,18 @@
+//===-- Implementation header for nexttowardf -------------------*- 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_NEXTTOWARDF_H
+#define LLVM_LIBC_SRC_MATH_NEXTTOWARDF_H
+
+namespace LIBC_NAMESPACE {
+
+float nexttowardf(float x, long double y);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_MATH_NEXTTOWARDF_H
diff --git a/libc/src/math/nexttowardl.h b/libc/src/math/nexttowardl.h
new file mode 100644
index 000000000000000..be1d8b298185d61
--- /dev/null
+++ b/libc/src/math/nexttowardl.h
@@ -0,0 +1,18 @@
+//===-- Implementation header for nexttowardl -------------------*- 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_NEXTTOWARDL_H
+#define LLVM_LIBC_SRC_MATH_NEXTTOWARDL_H
+
+namespace LIBC_NAMESPACE {
+
+long double nexttowardl(long double x, long double y);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_MATH_NEXTTOWARDL_H
diff --git a/libc/test/src/math/smoke/CMakeLists.txt b/libc/test/src/math/smoke/CMakeLists.txt
index 101bdac995355de..298a1b1a400f1d8 100644
--- a/libc/test/src/math/smoke/CMakeLists.txt
+++ b/libc/test/src/math/smoke/CMakeLists.txt
@@ -1251,6 +1251,54 @@ add_fp_unittest(
libc.src.__support.FPUtil.fp_bits
)
+# FIXME: These tests are currently spurious for NVPTX.
+if(NOT LIBC_GPU_TARGET_ARCHITECTURE_IS_NVPTX)
+ add_fp_unittest(
+ nexttoward_test
+ SUITE
+ libc-math-smoke-tests
+ SRCS
+ nexttoward_test.cpp
+ HDRS
+ NextTowardTest.h
+ DEPENDS
+ libc.include.math
+ libc.src.math.nexttoward
+ libc.src.__support.FPUtil.basic_operations
+ libc.src.__support.FPUtil.fp_bits
+ )
+
+ add_fp_unittest(
+ nexttowardf_test
+ SUITE
+ libc-math-smoke-tests
+ SRCS
+ nexttowardf_test.cpp
+ HDRS
+ NextTowardTest.h
+ DEPENDS
+ libc.include.math
+ libc.src.math.nexttowardf
+ libc.src.__support.FPUtil.basic_operations
+ libc.src.__support.FPUtil.fp_bits
+ )
+endif()
+
+add_fp_unittest(
+ nexttowardl_test
+ SUITE
+ libc-math-smoke-tests
+ SRCS
+ nexttowardl_test.cpp
+ HDRS
+ NextTowardTest.h
+ DEPENDS
+ libc.include.math
+ libc.src.math.nexttowardl
+ libc.src.__support.FPUtil.basic_operations
+ libc.src.__support.FPUtil.fp_bits
+)
+
# TODO(lntue): The current implementation of fputil::general::fma<float> is only
# correctly rounded for the default rounding mode round-to-nearest tie-to-even.
add_fp_unittest(
diff --git a/libc/test/src/math/smoke/NextTowardTest.h b/libc/test/src/math/smoke/NextTowardTest.h
new file mode 100644
index 000000000000000..4d27592a11422bf
--- /dev/null
+++ b/libc/test/src/math/smoke/NextTowardTest.h
@@ -0,0 +1,223 @@
+//===-- Utility class to test different flavors of nexttoward ---*- 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_SRC_MATH_NEXTTOWARDTEST_H
+#define LLVM_LIBC_TEST_SRC_MATH_NEXTTOWARDTEST_H
+
+#include "src/__support/CPP/bit.h"
+#include "src/__support/CPP/type_traits.h"
+#include "src/__support/FPUtil/BasicOperations.h"
+#include "src/__support/FPUtil/FPBits.h"
+#include "test/UnitTest/FPMatcher.h"
+#include "test/UnitTest/Test.h"
+#include <fenv.h>
+#include <math.h>
+
+#define ASSERT_FP_EQ_WITH_EXCEPTION(result, expected, expected_exception) \
+ ASSERT_FP_EQ(result, expected); \
+ ASSERT_FP_EXCEPTION(expected_exception); \
+ LIBC_NAMESPACE::fputil::clear_except(FE_ALL_EXCEPT)
+
+#define ASSERT_FP_EQ_WITH_UNDERFLOW(result, expected) \
+ ASSERT_FP_EQ_WITH_EXCEPTION(result, expected, FE_INEXACT | FE_UNDERFLOW)
+
+#define ASSERT_FP_EQ_WITH_OVERFLOW(result, expected) \
+ ASSERT_FP_EQ_WITH_EXCEPTION(result, expected, FE_INEXACT | FE_OVERFLOW)
+
+template <typename T>
+class NextTowardTestTemplate : public LIBC_NAMESPACE::testing::Test {
+ using FPBits = LIBC_NAMESPACE::fputil::FPBits<T>;
+ using ToFPBits = LIBC_NAMESPACE::fputil::FPBits<long double>;
+ using MantissaWidth = LIBC_NAMESPACE::fputil::MantissaWidth<T>;
+ using UIntType = typename FPBits::UIntType;
+
+ static constexpr int BIT_WIDTH_OF_TYPE =
+ LIBC_NAMESPACE::fputil::FloatProperties<T>::BIT_WIDTH;
+
+ const T zero = T(FPBits::zero());
+ const T neg_zero = T(FPBits::neg_zero());
+ const T inf = T(FPBits::inf());
+ const T neg_inf = T(FPBits::neg_inf());
+ const T nan = T(FPBits::build_quiet_nan(1));
+
+ const long double to_zero = ToFPBits::zero();
+ const long double to_neg_zero = ToFPBits::neg_zero();
+ const long double to_nan = ToFPBits::build_quiet_nan(1);
+
+ const UIntType min_subnormal = FPBits::MIN_SUBNORMAL;
+ const UIntType max_subnormal = FPBits::MAX_SUBNORMAL;
+ const UIntType min_normal = FPBits::MIN_NORMAL;
+ const UIntType max_normal = FPBits::MAX_NORMAL;
+
+public:
+ typedef T (*NextTowardFunc)(T, long double);
+
+ void testNaN(NextTowardFunc func) {
+ ASSERT_FP_EQ(func(nan, 0), nan);
+ ASSERT_FP_EQ(func(0, to_nan), nan);
+ }
+
+ void testBoundaries(NextTowardFunc func) {
+ ASSERT_FP_EQ(func(zero, to_neg_zero), neg_zero);
+ ASSERT_FP_EQ(func(neg_zero, to_zero), zero);
+
+ // 'from' is zero|neg_zero.
+ T x = zero;
+ T result = func(x, 1);
+ UIntType expected_bits = 1;
+ T expected = LIBC_NAMESPACE::cpp::bit_cast<T>(expected_bits);
+ ASSERT_FP_EQ_WITH_UNDERFLOW(result, expected);
+
+ result = func(x, -1);
+ expected_bits = (UIntType(1) << (BIT_WIDTH_OF_TYPE - 1)) + 1;
+ expected = LIBC_NAMESPACE::cpp::bit_cast<T>(expected_bits);
+ ASSERT_FP_EQ_WITH_UNDERFLOW(result, expected);
+
+ x = n...
[truncated]
|
nishantwrp
commented
Nov 18, 2023
nishantwrp
commented
Nov 18, 2023
Comment on lines
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| UIntType exponent_bits = int_val & FloatProperties<T>::EXPONENT_MASK; | ||
| if (exponent_bits == UIntType(0)) | ||
| raise_except_if_required(FE_UNDERFLOW | FE_INEXACT); | ||
| else if (exponent_bits == FloatProperties<T>::EXPONENT_MASK) | ||
| raise_except_if_required(FE_OVERFLOW | FE_INEXACT); |
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Should probably test the exceptions in the tests for nextafter too. Will do that in a separate pr?
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SGTM. Thanks for fixing this TODO item.
lntue
reviewed
Nov 19, 2023
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| template <typename T, cpp::enable_if_t<cpp::is_floating_point_v<T>, int> = 0> | ||
| LIBC_INLINE T nexttoward(T from, long double to) { |
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For free function, I personally prefer to use SFINAE on the returning type LIBC_INLINE cpp::enable_if_t<cpp::is_floating_point_v<T>, T> nexttoward(...), so that it frees the second template parameter to be used if needed.
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done. just out of curiosity, what is the functional difference b/w the two approaches?
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Essentially, when we do SFINAE with template<T, U = enable_if_t<..., void>>, we do not intend to let user use the second template parameter, but nothing prevents user code to be func<T, U>(...), and it might silently get wrong function. If all users do is to call func(...) or func<T> then it doesn't matter.
lntue
reviewed
Nov 19, 2023
lntue
reviewed
Nov 19, 2023
lntue
reviewed
Nov 19, 2023
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Thanks for adding these functions! Overall LGTM with a few nits. Do you mind also updating the followings:
- bazel build: https://github.com/llvm/llvm-project/blob/main/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
- progress documentation: https://github.com/llvm/llvm-project/blob/main/libc/docs/math/index.rst
Thanks!
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I've addressed the review comments, please review @lntue |
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✅ With the latest revision this PR passed the C/C++ code formatter. |
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Nov 21, 2023
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Follow up to #72763 (comment). ### Summary - Add unit tests for raising excepts in `nextafter`. - Fixed a bug in testing code for `nexttoward`. cc: @lntue
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| FPBits<long double> to_bits(to); | ||
| if (to_bits.is_nan()) | ||
| return to; |
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I'm observing the following warnings when building ninja check-libc with clang:
[286/3491] Building CXX object projects/libc/src/math/gene...es/libc.src.math.generic.nexttowardf.dir/nexttowardf.cpp.o
In file included from /android0/llvm-project/libc/src/math/generic/nexttowardf.cpp:10:
/android0/llvm-project/libc/src/__support/FPUtil/ManipulationFunctions.h:191:12: warning: implicit conversion loses floating-point precision: 'long double' to 'cpp::enable_if_t<cpp::is_floating_point_v<float>, float>' (aka 'float') [-Wimplicit-float-conversion]
return to;
~~~~~~ ^~
/android0/llvm-project/libc/src/math/generic/nexttowardf.cpp:16:18: note: in instantiation of function template specialization '__llvm_libc_18_0_0_git::fputil::nexttoward<float>' requested here
return fputil::nexttoward(x, y);
^
In file included from /android0/llvm-project/libc/src/math/generic/nexttowardf.cpp:10:
/android0/llvm-project/libc/src/__support/FPUtil/ManipulationFunctions.h:194:12: warning: implicit conversion loses floating-point precision: 'long double' to 'cpp::enable_if_t<cpp::is_floating_point_v<float>, float>' (aka 'float') [-Wimplicit-float-conversion]
return to;
~~~~~~ ^~
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That issue should be fixed by #73698. Are you on an updated checkout?
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ah, thanks, slightly behind!
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Implements the
nexttoward,nexttowardfandnexttowardlfunctions. Also, raise excepts required by the standard innextafterfunctions.cc: @lntue