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c4be334400
It removes the wrapper by moving the error/EDOM handling to an out-of-line implementation (__math_invalid_i/__math_invalid_li). Also, __glibc_unlikely is used on errors case since it helps code generation on recent gcc. The code now builds to with gcc-14 on aarch64: 0000000000000000 <__ilogb>: 0: 9e660000 fmov x0, d0 4: d374f801 ubfx x1, x0, #52, #11 8: 340000e1 cbz w1, 24 <__ilogb+0x24> c: 510ffc20 sub w0, w1, #0x3ff 10: 711ffc3f cmp w1, #0x7ff 14: 54000040 b.eq 1c <__ilogb+0x1c> // b.none 18: d65f03c0 ret 1c: 12b00000 mov w0, #0x7fffffff // #2147483647 20: 14000000 b 0 <__math_invalid_i> 24: d374cc00 lsl x0, x0, #12 28: b40000a0 cbz x0, 3c <__ilogb+0x3c> 2c: dac01000 clz x0, x0 30: 12807fc1 mov w1, #0xfffffc01 // #-1023 34: 4b000020 sub w0, w1, w0 38: d65f03c0 ret 3c: 320107e0 mov w0, #0x80000001 // #-2147483647 40: 14000000 b 0 <__math_invalid_i> Some ABI requires additional adjustments: * i386 and m68k requires to use the template version, since both provide __ieee754_ilogb implementatations. * loongarch uses a custom implementation as well. * powerpc64le also has a custom implementation for POWER9, which is also used for float and float128 version. The generic e_ilogb.c implementation is moved on powerpc to keep the current code as-is. Checked on aarch64-linux-gnu and x86_64-linux-gnu. Reviewed-by: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
131 lines
2.8 KiB
C
131 lines
2.8 KiB
C
/* Double-precision math error handling.
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Copyright (C) 2018-2025 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <math-barriers.h>
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#include "math_config.h"
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#if WANT_ERRNO
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#include <errno.h>
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/* NOINLINE reduces code size and avoids making math functions non-leaf
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when the error handling is inlined. */
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NOINLINE static double
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with_errno (double y, int e)
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{
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errno = e;
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return y;
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}
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NOINLINE static int
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with_errno_i (int y, int e)
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{
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errno = e;
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return y;
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}
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NOINLINE static long int
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with_errno_li (long int y, int e)
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{
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errno = e;
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return y;
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}
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#else
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#define with_errno(x, e) (x)
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#define with_errno_i(x, e) (x)
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#define with_errno_li(x, e) (x)
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#endif
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attribute_hidden double
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__math_edom (double y)
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{
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return with_errno (y, EDOM);
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}
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/* NOINLINE reduces code size. */
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NOINLINE static double
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xflow (uint32_t sign, double y)
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{
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y = math_opt_barrier (sign ? -y : y) * y;
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return with_errno (y, ERANGE);
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}
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attribute_hidden double
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__math_uflow (uint32_t sign)
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{
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return xflow (sign, 0x1p-767);
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}
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#if WANT_ERRNO_UFLOW
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/* Underflows to zero in some non-nearest rounding mode, setting errno
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is valid even if the result is non-zero, but in the subnormal range. */
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attribute_hidden double
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__math_may_uflow (uint32_t sign)
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{
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return xflow (sign, 0x1.8p-538);
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}
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#endif
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attribute_hidden double
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__math_oflow (uint32_t sign)
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{
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return xflow (sign, 0x1p769);
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}
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attribute_hidden double
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__math_divzero (uint32_t sign)
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{
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double y = math_opt_barrier (sign ? -1.0 : 1.0) / 0.0;
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return with_errno (y, ERANGE);
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}
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attribute_hidden double
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__math_invalid (double x)
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{
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double y = (x - x) / (x - x);
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return isnan (x) ? y : with_errno (y, EDOM);
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}
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attribute_hidden int
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__math_invalid_i (int r)
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{
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double y = 0.0 / 0.0;
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math_force_eval (y);
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return with_errno_i (r, EDOM);
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}
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attribute_hidden long int
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__math_invalid_li (long int r)
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{
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double y = 0.0 / 0.0;
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math_force_eval (y);
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return with_errno_li (r, EDOM);
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}
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/* Check result and set errno if necessary. */
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attribute_hidden double
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__math_check_uflow (double y)
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{
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return y == 0.0 ? with_errno (y, ERANGE) : y;
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}
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attribute_hidden double
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__math_check_oflow (double y)
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{
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return isinf (y) ? with_errno (y, ERANGE) : y;
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}
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