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40e6575aa3
This is more spec-compliant because it does not rely on dead-code elimination by the compiler. Especially MSVC has problems with this, as can be seen in https://ffmpeg.org/pipermail/ffmpeg-devel/2022-May/296373.html or https://ffmpeg.org/pipermail/ffmpeg-devel/2022-May/297022.html This commit does not eliminate every instance where we rely on dead code elimination: It only tackles branching to the initialization of arch-specific dsp code, not e.g. all uses of CONFIG_ and HAVE_ checks. But maybe it is already enough to compile FFmpeg with MSVC with whole-programm-optimizations enabled (if one does not disable too many components). Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
105 lines
3.4 KiB
C
105 lines
3.4 KiB
C
/*
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* SIMD optimized non-power-of-two MDCT functions
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*
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* Copyright (C) 2017 Rostislav Pehlivanov <atomnuker@gmail.com>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg 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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*
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* FFmpeg 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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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <string.h>
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#include "config.h"
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#include "libavutil/attributes.h"
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#include "libavutil/x86/cpu.h"
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#include "libavcodec/mdct15.h"
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void ff_mdct15_postreindex_sse3(FFTComplex *out, FFTComplex *in, FFTComplex *exp, int *lut, ptrdiff_t len8);
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void ff_mdct15_postreindex_avx2(FFTComplex *out, FFTComplex *in, FFTComplex *exp, int *lut, ptrdiff_t len8);
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void ff_fft15_avx(FFTComplex *out, FFTComplex *in, FFTComplex *exptab, ptrdiff_t stride);
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static void perm_twiddles(MDCT15Context *s)
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{
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int k;
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FFTComplex tmp[30];
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/* 5-point FFT twiddles */
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s->exptab[60].re = s->exptab[60].im = s->exptab[19].re;
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s->exptab[61].re = s->exptab[61].im = s->exptab[19].im;
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s->exptab[62].re = s->exptab[62].im = s->exptab[20].re;
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s->exptab[63].re = s->exptab[63].im = s->exptab[20].im;
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/* 15-point FFT twiddles */
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for (k = 0; k < 5; k++) {
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tmp[6*k + 0] = s->exptab[k + 0];
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tmp[6*k + 2] = s->exptab[k + 5];
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tmp[6*k + 4] = s->exptab[k + 10];
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tmp[6*k + 1] = s->exptab[2 * (k + 0)];
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tmp[6*k + 3] = s->exptab[2 * (k + 5)];
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tmp[6*k + 5] = s->exptab[2 * k + 5 ];
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}
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for (k = 0; k < 6; k++) {
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FFTComplex ac_exp[] = {
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{ tmp[6*1 + k].re, tmp[6*1 + k].re },
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{ tmp[6*2 + k].re, tmp[6*2 + k].re },
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{ tmp[6*3 + k].re, tmp[6*3 + k].re },
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{ tmp[6*4 + k].re, tmp[6*4 + k].re },
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{ tmp[6*1 + k].im, -tmp[6*1 + k].im },
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{ tmp[6*2 + k].im, -tmp[6*2 + k].im },
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{ tmp[6*3 + k].im, -tmp[6*3 + k].im },
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{ tmp[6*4 + k].im, -tmp[6*4 + k].im },
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};
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memcpy(s->exptab + 8*k, ac_exp, 8*sizeof(FFTComplex));
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}
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/* Specialcase when k = 0 */
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for (k = 0; k < 3; k++) {
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FFTComplex dc_exp[] = {
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{ tmp[2*k + 0].re, -tmp[2*k + 0].im },
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{ tmp[2*k + 0].im, tmp[2*k + 0].re },
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{ tmp[2*k + 1].re, -tmp[2*k + 1].im },
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{ tmp[2*k + 1].im, tmp[2*k + 1].re },
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};
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memcpy(s->exptab + 8*6 + 4*k, dc_exp, 4*sizeof(FFTComplex));
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}
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}
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av_cold void ff_mdct15_init_x86(MDCT15Context *s)
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{
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int adjust_twiddles = 0;
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int cpu_flags = av_get_cpu_flags();
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if (EXTERNAL_SSE3(cpu_flags))
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s->postreindex = ff_mdct15_postreindex_sse3;
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#if ARCH_X86_64
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if (EXTERNAL_AVX(cpu_flags)) {
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s->fft15 = ff_fft15_avx;
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adjust_twiddles = 1;
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}
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if (EXTERNAL_AVX2_FAST(cpu_flags))
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s->postreindex = ff_mdct15_postreindex_avx2;
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#endif
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if (adjust_twiddles)
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perm_twiddles(s);
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}
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