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Differential D117628

[libc] Remove as_double usage as constant initializations in sincosf implementation.
ClosedPublic

Authored by lntue on Jan 18 2022, 5:18 PM.

Details

Reviewers
abrachet
michaelrj
sivachandra
Commits
rGb0cd3abf032e: [libc] Remove as_double usage as constant initializations in sincosf…
Summary

Use hexadecimal floats with C++17 instead of as_double as floating point constant initializations.

Diff Detail

Event Timeline

lntue created this revision.Jan 18 2022, 5:18 PM
Herald added a project: Restricted Project. · View Herald TranscriptJan 18 2022, 5:18 PM
Herald added subscribers: ecnelises, tschuett, mgorny. · View Herald Transcript
lntue requested review of this revision.Jan 18 2022, 5:18 PM
Harbormaster completed remote builds in B144174: Diff 401055.Jan 18 2022, 7:26 PM
sivachandra accepted this revision.Jan 18 2022, 8:47 PM
This revision is now accepted and ready to land.Jan 18 2022, 8:47 PM
Closed by commit rGb0cd3abf032e: [libc] Remove as_double usage as constant initializations in sincosf… (authored by lntue). · Explain WhyJan 18 2022, 8:49 PM
This revision was automatically updated to reflect the committed changes.
lntue added a commit: rGb0cd3abf032e: [libc] Remove as_double usage as constant initializations in sincosf….

Revision Contents

PathSize
libc/
src/
math/
generic/
4 lines
18 lines
44 lines
4 lines

Diff 401089

libc/src/math/generic/CMakeLists.txt

Show All 38 Linesadd_object_library(
SRCS SRCS
math_utils.cpp math_utils.cpp
HDRS HDRS
math_utils.h math_utils.h
DEPENDS DEPENDS
libc.include.errno libc.include.errno
libc.include.math libc.include.math
libc.src.errno.__errno_location libc.src.errno.__errno_location
COMPILE_OPTIONS
-Wno-c++17-extensions
) )
add_object_library( add_object_library(
sincosf_utils sincosf_utils
HDRS HDRS
sincosf_utils.h sincosf_utils.h
SRCS SRCS
sincosf_data.cpp sincosf_data.cpp
DEPENDS DEPENDS
.math_utils .math_utils
COMPILE_OPTIONS
-Wno-c++17-extensions
) )
add_entrypoint_object( add_entrypoint_object(
cosf cosf
SRCS SRCS
cosf.cpp cosf.cpp
HDRS HDRS
../cosf.h ../cosf.h
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libc/src/math/generic/math_utils.cpp

//===-- Implementation of math utils --------------------------------------===// //===-- Implementation of math utils --------------------------------------===//
// //
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information. // See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// //
//===----------------------------------------------------------------------===// //===----------------------------------------------------------------------===//
#include "math_utils.h" #include "math_utils.h"
namespace __llvm_libc { namespace __llvm_libc {
const float XFlowValues<float>::overflow_value = constexpr float XFlowValues<float>::overflow_value = 0x1p97f;
as_float(0x70000000); // 0x1p97f constexpr float XFlowValues<float>::underflow_value = 0x1p-95f;
const float XFlowValues<float>::underflow_value = constexpr float XFlowValues<float>::may_underflow_value = 0x1.4p-75f;
as_float(0x10000000); // 0x1p97f
const float XFlowValues<float>::may_underflow_value =
as_float(0x1a200000); // 0x1.4p-75f
const double XFlowValues<double>::overflow_value = constexpr double XFlowValues<double>::overflow_value = 0x1p769;
as_double(0x7000000000000000); // 0x1p769 constexpr double XFlowValues<double>::underflow_value = 0x1p-767;
const double XFlowValues<double>::underflow_value = constexpr double XFlowValues<double>::may_underflow_value = 0x1.8p-538;
as_double(0x1000000000000000); // 0x1p-767
const double XFlowValues<double>::may_underflow_value =
as_double(0x1e58000000000000); // 0x1.8p-538
} // namespace __llvm_libc } // namespace __llvm_libc

libc/src/math/generic/sincosf_data.cpp

Show All 9 Lines
#include "sincosf_utils.h" #include "sincosf_utils.h"
#include <stdint.h> #include <stdint.h>
namespace __llvm_libc { namespace __llvm_libc {
// The constants and polynomials for sine and cosine. The 2nd entry // The constants and polynomials for sine and cosine. The 2nd entry
// computes -cos (x) rather than cos (x) to get negation for free. // computes -cos (x) rather than cos (x) to get negation for free.
const sincos_t __SINCOSF_TABLE[2] = { constexpr sincos_t __SINCOSF_TABLE[2] = {
{{1.0, -1.0, -1.0, 1.0}, {{1.0, -1.0, -1.0, 1.0},
as_double(0x41645f306dc9c883), 0x1.45f306dc9c883p+23,
as_double(0x3ff921fb54442d18), 0x1.921fb54442d18p+0,
as_double(0x3ff0000000000000), 0x1p+0,
as_double(0xbfdffffffd0c621c), -0x1.ffffffd0c621cp-2,
as_double(0x3fa55553e1068f19), 0x1.55553e1068f19p-5,
as_double(0xbf56c087e89a359d), -0x1.6c087e89a359dp-10,
as_double(0x3ef99343027bf8c3), 0x1.99343027bf8c3p-16,
as_double(0xbfc555545995a603), -0x1.555545995a603p-3,
as_double(0x3f81107605230bc4), 0x1.1107605230bc4p-7,
as_double(0xbf2994eb3774cf24)}, -0x1.994eb3774cf24p-13},
{{1.0, -1.0, -1.0, 1.0}, {{1.0, -1.0, -1.0, 1.0},
as_double(0x41645f306dc9c883), 0x1.45f306dc9c883p+23,
as_double(0x3ff921fb54442d18), 0x1.921fb54442d18p+0,
as_double(0xbff0000000000000), -0x1p+0,
as_double(0x3fdffffffd0c621c), 0x1.ffffffd0c621cp-2,
as_double(0xbfa55553e1068f19), -0x1.55553e1068f19p-5,
as_double(0x3f56c087e89a359d), 0x1.6c087e89a359dp-10,
as_double(0xbef99343027bf8c3), -0x1.99343027bf8c3p-16,
as_double(0xbfc555545995a603), -0x1.555545995a603p-3,
as_double(0x3f81107605230bc4), 0x1.1107605230bc4p-7,
as_double(0xbf2994eb3774cf24)}, -0x1.994eb3774cf24p-13},
}; };
// Table with 4/PI to 192 bit precision. To avoid unaligned accesses // Table with 4/PI to 192 bit precision. To avoid unaligned accesses
// only 8 new bits are added per entry, making the table 4 times larger. // only 8 new bits are added per entry, making the table 4 times larger.
const uint32_t __INV_PIO4[24] = { constexpr uint32_t __INV_PIO4[24] = {
0xa2, 0xa2f9, 0xa2f983, 0xa2f9836e, 0xf9836e4e, 0x836e4e44, 0xa2, 0xa2f9, 0xa2f983, 0xa2f9836e, 0xf9836e4e, 0x836e4e44,
0x6e4e4415, 0x4e441529, 0x441529fc, 0x1529fc27, 0x29fc2757, 0xfc2757d1, 0x6e4e4415, 0x4e441529, 0x441529fc, 0x1529fc27, 0x29fc2757, 0xfc2757d1,
0x2757d1f5, 0x57d1f534, 0xd1f534dd, 0xf534ddc0, 0x34ddc0db, 0xddc0db62, 0x2757d1f5, 0x57d1f534, 0xd1f534dd, 0xf534ddc0, 0x34ddc0db, 0xddc0db62,
0xc0db6295, 0xdb629599, 0x6295993c, 0x95993c43, 0x993c4390, 0x3c439041}; 0xc0db6295, 0xdb629599, 0x6295993c, 0x95993c43, 0x993c4390, 0x3c439041};
} // namespace __llvm_libc } // namespace __llvm_libc

libc/src/math/generic/sincosf_utils.h

Show All 10 Lines
#include "math_utils.h" #include "math_utils.h"
#include <stdint.h> #include <stdint.h>
namespace __llvm_libc { namespace __llvm_libc {
// 2PI * 2^-64. // 2PI * 2^-64.
static const double pi63 = as_double(0x3c1921fb54442d18); static constexpr double pi63 = 0x1.921fb54442d18p-62;
// PI / 4. // PI / 4.
static const double pio4 = as_double(0x3fe921fb54442d18); static constexpr double pio4 = 0x1.921fb54442d18p-1;
// The constants and polynomials for sine and cosine. // The constants and polynomials for sine and cosine.
typedef struct { typedef struct {
double sign[4]; // Sign of sine in quadrants 0..3. double sign[4]; // Sign of sine in quadrants 0..3.
double hpi_inv; // 2 / PI ( * 2^24 ). double hpi_inv; // 2 / PI ( * 2^24 ).
double hpi; // PI / 2. double hpi; // PI / 2.
double c0, c1, c2, c3, c4; // Cosine polynomial. double c0, c1, c2, c3, c4; // Cosine polynomial.
double s1, s2, s3; // Sine polynomial. double s1, s2, s3; // Sine polynomial.
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