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[libc][math] Update getpayload and fmul with NaN inputs. #99812

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Merged
merged 5 commits into from
Jul 21, 2024
Merged

[libc][math] Update getpayload and fmul with NaN inputs. #99812

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8ef05d3
[libc][math] Update getpayload and fmul with NaN inputs.
lntue Jul 21, 2024
0570965
Address comments and fix the same issue for add_sub, div, and FMA.
lntue Jul 21, 2024
dbd831d
Fix add + sub tests and fma.
lntue Jul 21, 2024
1e4d04e
Add missing mul entrypoints for riscv.
lntue Jul 21, 2024
fb6525d
Update DivTest.h
lntue Jul 21, 2024
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2 changes: 2 additions & 0 deletions libc/config/linux/riscv/entrypoints.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -377,6 +377,7 @@ set(TARGET_LIBM_ENTRYPOINTS
libc.src.math.cosf
libc.src.math.coshf
libc.src.math.cospif
libc.src.math.dmull
libc.src.math.dsqrtl
libc.src.math.erff
libc.src.math.exp
Expand Down Expand Up @@ -434,6 +435,7 @@ set(TARGET_LIBM_ENTRYPOINTS
libc.src.math.fmodf
libc.src.math.fmodl
libc.src.math.fmul
libc.src.math.fmull
libc.src.math.frexp
libc.src.math.frexpf
libc.src.math.frexpl
Expand Down
13 changes: 11 additions & 2 deletions libc/src/__support/FPUtil/BasicOperations.h
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Original file line number Diff line number Diff line change
Expand Up @@ -11,8 +11,8 @@

#include "FEnvImpl.h"
#include "FPBits.h"
#include "dyadic_float.h"

#include "FEnvImpl.h"
#include "src/__support/CPP/type_traits.h"
#include "src/__support/common.h"
#include "src/__support/macros/config.h"
Expand Down Expand Up @@ -269,12 +269,21 @@ totalordermag(T x, T y) {
template <typename T>
LIBC_INLINE cpp::enable_if_t<cpp::is_floating_point_v<T>, T> getpayload(T x) {
using FPBits = FPBits<T>;
using StorageType = typename FPBits::StorageType;
FPBits x_bits(x);

if (!x_bits.is_nan())
return T(-1.0);

return T(x_bits.uintval() & (FPBits::FRACTION_MASK >> 1));
StorageType payload = x_bits.uintval() & (FPBits::FRACTION_MASK >> 1);

if constexpr (is_big_int_v<StorageType>) {
DyadicFloat<FPBits::STORAGE_LEN> payload_dfloat(Sign::POS, 0, payload);

return static_cast<T>(payload_dfloat);
} else {
return static_cast<T>(payload);
}
}

template <bool IsSignaling, typename T>
Expand Down
57 changes: 29 additions & 28 deletions libc/src/__support/FPUtil/CMakeLists.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -75,19 +75,6 @@ add_header_library(
libc.src.__support.common
)

add_header_library(
basic_operations
HDRS
BasicOperations.h
DEPENDS
.fp_bits
.fenv_impl
libc.src.__support.CPP.type_traits
libc.src.__support.uint128
libc.src.__support.common
libc.src.__support.macros.optimization
)

add_header_library(
division_and_remainder_operations
HDRS
Expand All @@ -113,21 +100,6 @@ add_header_library(
)


add_header_library(
hypot
HDRS
Hypot.h
DEPENDS
.basic_operations
.fenv_impl
.fp_bits
.rounding_mode
libc.src.__support.common
libc.src.__support.CPP.bit
libc.src.__support.CPP.type_traits
libc.src.__support.uint128
)

add_header_library(
sqrt
HDRS
Expand Down Expand Up @@ -208,6 +180,35 @@ add_header_library(
libc.src.__support.macros.optimization
)

add_header_library(
basic_operations
HDRS
BasicOperations.h
DEPENDS
.dyadic_float
.fp_bits
.fenv_impl
libc.src.__support.CPP.type_traits
libc.src.__support.uint128
libc.src.__support.common
libc.src.__support.macros.optimization
)

add_header_library(
hypot
HDRS
Hypot.h
DEPENDS
.basic_operations
.fenv_impl
.fp_bits
.rounding_mode
libc.src.__support.common
libc.src.__support.CPP.bit
libc.src.__support.CPP.type_traits
libc.src.__support.uint128
)

add_header_library(
manipulation_functions
HDRS
Expand Down
45 changes: 27 additions & 18 deletions libc/src/__support/FPUtil/generic/FMA.h
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Original file line number Diff line number Diff line change
Expand Up @@ -129,27 +129,27 @@ fma(InType x, InType y, InType z) {
raise_except_if_required(FE_INVALID);

if (x_bits.is_quiet_nan()) {
InStorageType x_payload = static_cast<InStorageType>(getpayload(x));
if ((x_payload & ~(OutFPBits::FRACTION_MASK >> 1)) == 0)
return OutFPBits::quiet_nan(x_bits.sign(),
static_cast<OutStorageType>(x_payload))
.get_val();
InStorageType x_payload = x_bits.get_mantissa();
x_payload >>= InFPBits::FRACTION_LEN - OutFPBits::FRACTION_LEN;
return OutFPBits::quiet_nan(x_bits.sign(),
static_cast<OutStorageType>(x_payload))
.get_val();
}

if (y_bits.is_quiet_nan()) {
InStorageType y_payload = static_cast<InStorageType>(getpayload(y));
if ((y_payload & ~(OutFPBits::FRACTION_MASK >> 1)) == 0)
return OutFPBits::quiet_nan(y_bits.sign(),
static_cast<OutStorageType>(y_payload))
.get_val();
InStorageType y_payload = y_bits.get_mantissa();
y_payload >>= InFPBits::FRACTION_LEN - OutFPBits::FRACTION_LEN;
return OutFPBits::quiet_nan(y_bits.sign(),
static_cast<OutStorageType>(y_payload))
.get_val();
}

if (z_bits.is_quiet_nan()) {
InStorageType z_payload = static_cast<InStorageType>(getpayload(z));
if ((z_payload & ~(OutFPBits::FRACTION_MASK >> 1)) == 0)
return OutFPBits::quiet_nan(z_bits.sign(),
static_cast<OutStorageType>(z_payload))
.get_val();
InStorageType z_payload = z_bits.get_mantissa();
z_payload >>= InFPBits::FRACTION_LEN - OutFPBits::FRACTION_LEN;
return OutFPBits::quiet_nan(z_bits.sign(),
static_cast<OutStorageType>(z_payload))
.get_val();
}

return OutFPBits::quiet_nan().get_val();
Expand All @@ -163,18 +163,27 @@ fma(InType x, InType y, InType z) {
int y_exp = 0;
int z_exp = 0;

// Denormal scaling = 2^(fraction length).
constexpr InStorageType IMPLICIT_MASK =
InFPBits::SIG_MASK - InFPBits::FRACTION_MASK;

constexpr InType DENORMAL_SCALING =
InFPBits::create_value(
Sign::POS, InFPBits::FRACTION_LEN + InFPBits::EXP_BIAS, IMPLICIT_MASK)
.get_val();

// Normalize denormal inputs.
if (LIBC_UNLIKELY(InFPBits(x).is_subnormal())) {
x_exp -= InFPBits::FRACTION_LEN;
x *= InType(InStorageType(1) << InFPBits::FRACTION_LEN);
x *= DENORMAL_SCALING;
}
if (LIBC_UNLIKELY(InFPBits(y).is_subnormal())) {
y_exp -= InFPBits::FRACTION_LEN;
y *= InType(InStorageType(1) << InFPBits::FRACTION_LEN);
y *= DENORMAL_SCALING;
}
if (LIBC_UNLIKELY(InFPBits(z).is_subnormal())) {
z_exp -= InFPBits::FRACTION_LEN;
z *= InType(InStorageType(1) << InFPBits::FRACTION_LEN);
z *= DENORMAL_SCALING;
}

x_bits = InFPBits(x);
Expand Down
26 changes: 14 additions & 12 deletions libc/src/__support/FPUtil/generic/add_sub.h
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Original file line number Diff line number Diff line change
Expand Up @@ -56,19 +56,19 @@ add_or_sub(InType x, InType y) {
raise_except_if_required(FE_INVALID);

if (x_bits.is_quiet_nan()) {
InStorageType x_payload = static_cast<InStorageType>(getpayload(x));
if ((x_payload & ~(OutFPBits::FRACTION_MASK >> 1)) == 0)
return OutFPBits::quiet_nan(x_bits.sign(),
static_cast<OutStorageType>(x_payload))
.get_val();
InStorageType x_payload = x_bits.get_mantissa();
x_payload >>= InFPBits::FRACTION_LEN - OutFPBits::FRACTION_LEN;
return OutFPBits::quiet_nan(x_bits.sign(),
static_cast<OutStorageType>(x_payload))
.get_val();
}

if (y_bits.is_quiet_nan()) {
InStorageType y_payload = static_cast<InStorageType>(getpayload(y));
if ((y_payload & ~(OutFPBits::FRACTION_MASK >> 1)) == 0)
return OutFPBits::quiet_nan(y_bits.sign(),
static_cast<OutStorageType>(y_payload))
.get_val();
InStorageType y_payload = y_bits.get_mantissa();
y_payload >>= InFPBits::FRACTION_LEN - OutFPBits::FRACTION_LEN;
return OutFPBits::quiet_nan(y_bits.sign(),
static_cast<OutStorageType>(y_payload))
.get_val();
}

return OutFPBits::quiet_nan().get_val();
Expand Down Expand Up @@ -174,10 +174,12 @@ add_or_sub(InType x, InType y) {
else
aligned_min_mant_sticky = true;

InStorageType min_mant_sticky(static_cast<int>(aligned_min_mant_sticky));

if (is_effectively_add)
result_mant = max_mant + (aligned_min_mant | aligned_min_mant_sticky);
result_mant = max_mant + (aligned_min_mant | min_mant_sticky);
else
result_mant = max_mant - (aligned_min_mant | aligned_min_mant_sticky);
result_mant = max_mant - (aligned_min_mant | min_mant_sticky);
}

int result_exp = max_bits.get_exponent() - RESULT_FRACTION_LEN;
Expand Down
20 changes: 10 additions & 10 deletions libc/src/__support/FPUtil/generic/div.h
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Expand Up @@ -49,19 +49,19 @@ div(InType x, InType y) {
raise_except_if_required(FE_INVALID);

if (x_bits.is_quiet_nan()) {
InStorageType x_payload = static_cast<InStorageType>(getpayload(x));
if ((x_payload & ~(OutFPBits::FRACTION_MASK >> 1)) == 0)
return OutFPBits::quiet_nan(x_bits.sign(),
static_cast<OutStorageType>(x_payload))
.get_val();
InStorageType x_payload = x_bits.get_mantissa();
x_payload >>= InFPBits::FRACTION_LEN - OutFPBits::FRACTION_LEN;
return OutFPBits::quiet_nan(x_bits.sign(),
static_cast<OutStorageType>(x_payload))
.get_val();
}

if (y_bits.is_quiet_nan()) {
InStorageType y_payload = static_cast<InStorageType>(getpayload(y));
if ((y_payload & ~(OutFPBits::FRACTION_MASK >> 1)) == 0)
return OutFPBits::quiet_nan(y_bits.sign(),
static_cast<OutStorageType>(y_payload))
.get_val();
InStorageType y_payload = y_bits.get_mantissa();
y_payload >>= InFPBits::FRACTION_LEN - OutFPBits::FRACTION_LEN;
return OutFPBits::quiet_nan(y_bits.sign(),
static_cast<OutStorageType>(y_payload))
.get_val();
}

return OutFPBits::quiet_nan().get_val();
Expand Down
20 changes: 10 additions & 10 deletions libc/src/__support/FPUtil/generic/mul.h
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Original file line number Diff line number Diff line change
Expand Up @@ -50,19 +50,19 @@ mul(InType x, InType y) {
raise_except_if_required(FE_INVALID);

if (x_bits.is_quiet_nan()) {
InStorageType x_payload = static_cast<InStorageType>(getpayload(x));
if ((x_payload & ~(OutFPBits::FRACTION_MASK >> 1)) == 0)
return OutFPBits::quiet_nan(x_bits.sign(),
static_cast<OutStorageType>(x_payload))
.get_val();
InStorageType x_payload = x_bits.get_mantissa();
x_payload >>= InFPBits::FRACTION_LEN - OutFPBits::FRACTION_LEN;
return OutFPBits::quiet_nan(x_bits.sign(),
static_cast<OutStorageType>(x_payload))
.get_val();
}

if (y_bits.is_quiet_nan()) {
InStorageType y_payload = static_cast<InStorageType>(getpayload(y));
if ((y_payload & ~(OutFPBits::FRACTION_MASK >> 1)) == 0)
return OutFPBits::quiet_nan(y_bits.sign(),
static_cast<OutStorageType>(y_payload))
.get_val();
InStorageType y_payload = y_bits.get_mantissa();
y_payload >>= InFPBits::FRACTION_LEN - OutFPBits::FRACTION_LEN;
return OutFPBits::quiet_nan(y_bits.sign(),
static_cast<OutStorageType>(y_payload))
.get_val();
}

return OutFPBits::quiet_nan().get_val();
Expand Down
19 changes: 2 additions & 17 deletions libc/test/src/math/smoke/AddTest.h
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Expand Up @@ -38,23 +38,8 @@ class AddTest : public LIBC_NAMESPACE::testing::FEnvSafeTest {
EXPECT_FP_IS_NAN_WITH_EXCEPTION(func(sNaN, sNaN), FE_INVALID);

InType qnan_42 = InFPBits::quiet_nan(Sign::POS, 0x42).get_val();
EXPECT_FP_EQ(InType(0x42.0p+0),
LIBC_NAMESPACE::fputil::getpayload(func(qnan_42, zero)));
EXPECT_FP_EQ(InType(0x42.0p+0),
LIBC_NAMESPACE::fputil::getpayload(func(zero, qnan_42)));

if constexpr (sizeof(OutType) < sizeof(InType)) {
InStorageType max_payload = InFPBits::FRACTION_MASK >> 1;
InType qnan_max = InFPBits::quiet_nan(Sign::POS, max_payload).get_val();
EXPECT_FP_EQ(zero,
LIBC_NAMESPACE::fputil::getpayload(func(qnan_max, zero)));
EXPECT_FP_EQ(zero,
LIBC_NAMESPACE::fputil::getpayload(func(zero, qnan_max)));
EXPECT_FP_EQ(InType(0x42.0p+0),
LIBC_NAMESPACE::fputil::getpayload(func(qnan_max, qnan_42)));
EXPECT_FP_EQ(InType(0x42.0p+0),
LIBC_NAMESPACE::fputil::getpayload(func(qnan_42, qnan_max)));
}
EXPECT_FP_IS_NAN(func(qnan_42, zero));
EXPECT_FP_IS_NAN(func(zero, qnan_42));

EXPECT_FP_EQ(inf, func(inf, zero));
EXPECT_FP_EQ(neg_inf, func(neg_inf, zero));
Expand Down
19 changes: 2 additions & 17 deletions libc/test/src/math/smoke/DivTest.h
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Expand Up @@ -36,23 +36,8 @@ class DivTest : public LIBC_NAMESPACE::testing::FEnvSafeTest {
EXPECT_FP_IS_NAN_WITH_EXCEPTION(func(sNaN, sNaN), FE_INVALID);

InType qnan_42 = InFPBits::quiet_nan(Sign::POS, 0x42).get_val();
EXPECT_FP_EQ(InType(0x42.0p+0),
LIBC_NAMESPACE::fputil::getpayload(func(qnan_42, zero)));
EXPECT_FP_EQ(InType(0x42.0p+0),
LIBC_NAMESPACE::fputil::getpayload(func(zero, qnan_42)));

if constexpr (sizeof(OutType) < sizeof(InType)) {
InStorageType max_payload = InFPBits::FRACTION_MASK >> 1;
InType qnan_max = InFPBits::quiet_nan(Sign::POS, max_payload).get_val();
EXPECT_FP_EQ(zero,
LIBC_NAMESPACE::fputil::getpayload(func(qnan_max, zero)));
EXPECT_FP_EQ(zero,
LIBC_NAMESPACE::fputil::getpayload(func(zero, qnan_max)));
EXPECT_FP_EQ(InType(0x42.0p+0),
LIBC_NAMESPACE::fputil::getpayload(func(qnan_max, qnan_42)));
EXPECT_FP_EQ(InType(0x42.0p+0),
LIBC_NAMESPACE::fputil::getpayload(func(qnan_42, qnan_max)));
}
EXPECT_FP_IS_NAN(func(qnan_42, zero));
EXPECT_FP_IS_NAN(func(zero, qnan_42));

EXPECT_FP_EQ(inf, func(inf, zero));
EXPECT_FP_EQ(neg_inf, func(neg_inf, zero));
Expand Down
19 changes: 2 additions & 17 deletions libc/test/src/math/smoke/MulTest.h
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Expand Up @@ -38,23 +38,8 @@ class MulTest : public LIBC_NAMESPACE::testing::FEnvSafeTest {
EXPECT_FP_IS_NAN_WITH_EXCEPTION(func(sNaN, sNaN), FE_INVALID);

InType qnan_42 = InFPBits::quiet_nan(Sign::POS, 0x42).get_val();
EXPECT_FP_EQ(InType(0x42.0p+0),
LIBC_NAMESPACE::fputil::getpayload(func(qnan_42, zero)));
EXPECT_FP_EQ(InType(0x42.0p+0),
LIBC_NAMESPACE::fputil::getpayload(func(zero, qnan_42)));

if constexpr (sizeof(OutType) < sizeof(InType)) {
InStorageType max_payload = InFPBits::FRACTION_MASK >> 1;
InType qnan_max = InFPBits::quiet_nan(Sign::POS, max_payload).get_val();
EXPECT_FP_EQ(zero,
LIBC_NAMESPACE::fputil::getpayload(func(qnan_max, zero)));
EXPECT_FP_EQ(zero,
LIBC_NAMESPACE::fputil::getpayload(func(zero, qnan_max)));
EXPECT_FP_EQ(InType(0x42.0p+0),
LIBC_NAMESPACE::fputil::getpayload(func(qnan_max, qnan_42)));
EXPECT_FP_EQ(InType(0x42.0p+0),
LIBC_NAMESPACE::fputil::getpayload(func(qnan_42, qnan_max)));
}
EXPECT_FP_IS_NAN(func(qnan_42, zero));
EXPECT_FP_IS_NAN(func(zero, qnan_42));
Comment on lines +41 to +42
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Are you sure you don't want to check the payload?

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Yes, I don't think we need to be that strict on NaN propagation when it is underspecified in the standards, as long as the NaN semantic is preserved.


EXPECT_FP_EQ(inf, func(inf, InType(1.0)));
EXPECT_FP_EQ(neg_inf, func(neg_inf, InType(1.0)));
Expand Down
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