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1764683668
In particular, Clang defaults to FP contraction enabled. GCC defaults to off in standard C mode (-std=c11), but the C standard does not actually require any particular default. The #pragma STDC pragma, despite its name, warns on anything except Clang. Fixes: https://code.ffmpeg.org/FFmpeg/FFmpeg/issues/22796 See-also: https://discourse.llvm.org/t/fp-contraction-fma-on-by-default/64975 Signed-off-by: Niklas Haas <git@haasn.dev>
117 lines
3.2 KiB
C
117 lines
3.2 KiB
C
/**
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* Copyright (C) 2025 Niklas Haas
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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 "ops_backend.h"
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/**
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* We want to disable FP contraction because this is a reference backend that
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* establishes a bit-exact reference result.
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*/
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#ifdef __clang__
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#pragma STDC FP_CONTRACT OFF
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#elif AV_GCC_VERSION_AT_LEAST(4, 8)
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#pragma GCC optimize ("fp-contract=off")
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#elif defined(_MSC_VER)
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#pragma fp_contract (off)
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#endif
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#if AV_GCC_VERSION_AT_LEAST(4, 4)
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#pragma GCC optimize ("finite-math-only")
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#endif
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/* Array-based reference implementation */
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#ifndef SWS_BLOCK_SIZE
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# define SWS_BLOCK_SIZE 32
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#endif
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typedef uint8_t u8block_t[SWS_BLOCK_SIZE];
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typedef uint16_t u16block_t[SWS_BLOCK_SIZE];
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typedef uint32_t u32block_t[SWS_BLOCK_SIZE];
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typedef float f32block_t[SWS_BLOCK_SIZE];
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#define BIT_DEPTH 8
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# include "ops_tmpl_int.c"
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#undef BIT_DEPTH
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#define BIT_DEPTH 16
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# include "ops_tmpl_int.c"
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#undef BIT_DEPTH
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#define BIT_DEPTH 32
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# include "ops_tmpl_int.c"
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# include "ops_tmpl_float.c"
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#undef BIT_DEPTH
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static const SwsOpTable *const tables[] = {
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&bitfn(op_table_int, u8),
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&bitfn(op_table_int, u16),
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&bitfn(op_table_int, u32),
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&bitfn(op_table_float, f32),
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};
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static int compile(SwsContext *ctx, SwsOpList *ops, SwsCompiledOp *out)
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{
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int ret;
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SwsOpChain *chain = ff_sws_op_chain_alloc();
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if (!chain)
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return AVERROR(ENOMEM);
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av_assert0(ops->num_ops > 0);
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const SwsPixelType read_type = ops->ops[0].type;
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for (int i = 0; i < ops->num_ops; i++) {
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ret = ff_sws_op_compile_tables(ctx, tables, FF_ARRAY_ELEMS(tables),
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ops, i, SWS_BLOCK_SIZE, chain);
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if (ret < 0) {
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av_log(ctx, AV_LOG_TRACE, "Failed to compile op %d\n", i);
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ff_sws_op_chain_free(chain);
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return ret;
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}
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}
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*out = (SwsCompiledOp) {
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.slice_align = 1,
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.block_size = SWS_BLOCK_SIZE,
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.cpu_flags = chain->cpu_flags,
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.over_read = chain->over_read,
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.over_write = chain->over_write,
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.priv = chain,
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.free = ff_sws_op_chain_free_cb,
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};
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switch (read_type) {
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case SWS_PIXEL_U8: out->func = process_u8; break;
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case SWS_PIXEL_U16: out->func = process_u16; break;
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case SWS_PIXEL_U32: out->func = process_u32; break;
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case SWS_PIXEL_F32: out->func = process_f32; break;
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default: av_unreachable("Invalid pixel type!");
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}
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return 0;
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}
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const SwsOpBackend backend_c = {
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.name = "c",
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.compile = compile,
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.hw_format = AV_PIX_FMT_NONE,
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};
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