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d7025badd8
The powerpc32 implementations of llroundf and llround produce spurious and missing exceptions (some arising from such exceptions from conversions to long long, some present even when fctidz is used). This patch fixes those problems in a similar way to the llrint / llrintf fixes. The spurious exceptions in the fctidz case for large arguments arise from a converted value that saturated as LLONG_MAX being converted back to float or double (the conversion back being inexact, but "inexact" must not be raised together with "invalid"), and from the subtraction x - xrf also being inexact for sufficiently large arguments (whether the saturation was to LLONG_MAX or LLONG_MIN); those are fixed by returning early if the argument is large enough that no rounding is needed. This code is not used for --with-cpu=power4 builds (I suspect the code used in that case may also produce spurious "inexact" exceptions, but that's something to investigate later). Tested for powerpc. [BZ #19125] * sysdeps/powerpc/powerpc32/fpu/s_llround.c: Include <limits.h>, <math_private.h> and <stdint.h>. (__llround): Avoid conversions to and from long long int, and subtractions, where those might raise spurious exceptions. * sysdeps/powerpc/powerpc32/fpu/s_llroundf.c: Include <math_private.h> and <stdint.h>. (__llroundf): Avoid conversions to and from long long int, and subtractions, where those might raise spurious exceptions.
73 lines
2.3 KiB
C
73 lines
2.3 KiB
C
/* Round float value to long long int.
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Copyright (C) 1997-2015 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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<http://www.gnu.org/licenses/>. */
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#include <math.h>
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#include <math_private.h>
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#include <stdint.h>
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/* Round to the nearest integer, with values exactly on a 0.5 boundary
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rounded away from zero, regardless of the current rounding mode.
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If (long long)x, when x is out of range of a long long, clips at
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LLONG_MAX or LLONG_MIN, then this implementation also clips. */
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long long int
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__llroundf (float x)
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{
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long long xr;
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if (HAVE_PPC_FCTIDZ)
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xr = (long long) x;
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else
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{
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float ax = fabsf (x);
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/* Avoid incorrect exceptions from libgcc conversions (as of GCC
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5): <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59412>. */
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if (ax < 0x1p31f)
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xr = (long long int) (long int) x;
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else if (!(ax < 0x1p55f))
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xr = (long long int) (long int) (x * 0x1p-32f) << 32;
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else
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{
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uint32_t i0;
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GET_FLOAT_WORD (i0, x);
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int exponent = ((i0 >> 23) & 0xff) - 0x7f;
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unsigned long long int mant = (i0 & 0x7fffff) | 0x800000;
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mant <<= exponent - 23;
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xr = (long long int) ((i0 & 0x80000000) != 0 ? -mant : mant);
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}
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}
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/* Avoid spurious "inexact" converting LLONG_MAX to float, and from
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subtraction when the result is out of range, by returning early
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for arguments large enough that no rounding is needed. */
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if (!(fabsf (x) < 0x1p23f))
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return xr;
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float xrf = (float) xr;
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if (x >= 0.0)
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{
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if (x - xrf >= 0.5)
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xr += (long long) ((unsigned long long) xr + 1) > 0;
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}
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else
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{
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if (xrf - x >= 0.5)
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xr -= (long long) ((unsigned long long) xr - 1) < 0;
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}
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return xr;
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}
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weak_alias (__llroundf, llroundf)
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