This patch optimizes `IndexMask::from_bits` by making use of the fact that many bits can be processed at once and one does not have to look at every bit individual in many cases. Bits are stored as array of `BitInt` (aka `uint64_t`). So we can process at least 64 bits at a time. On some platforms we can also make use of SIMD and process up to 128 bits at once. This can significantly improve performance if all bits are set/unset. As a byproduct, this patch also optimizes `IndexMask::from_bools` which is now implemented in terms of `IndexMask::from_bits`. The conversion from bools to bits has been optimized significantly too by using SIMD intrinsics. Pull Request: https://projects.blender.org/blender/blender/pulls/126888
72 lines
1.9 KiB
C
72 lines
1.9 KiB
C
/* SPDX-FileCopyrightText: 2023 Blender Authors
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*
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* SPDX-License-Identifier: GPL-2.0-or-later */
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#pragma once
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/** \file
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* \ingroup bli
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*/
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#include "BLI_build_config.h"
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#include "BLI_math_inline.h"
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#include "BLI_utildefines.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* Search the value from LSB to MSB for a set bit. Returns index of this bit. */
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MINLINE int bitscan_forward_i(int a);
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MINLINE unsigned int bitscan_forward_uint(unsigned int a);
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MINLINE unsigned int bitscan_forward_uint64(unsigned long long a);
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/* Similar to above, but also clears the bit. */
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MINLINE int bitscan_forward_clear_i(int *a);
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MINLINE unsigned int bitscan_forward_clear_uint(unsigned int *a);
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/* Search the value from MSB to LSB for a set bit. Returns index of this bit. */
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MINLINE int bitscan_reverse_i(int a);
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MINLINE unsigned int bitscan_reverse_uint(unsigned int a);
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MINLINE unsigned int bitscan_reverse_uint64(unsigned long long a);
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/* Similar to above, but also clears the bit. */
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MINLINE int bitscan_reverse_clear_i(int *a);
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MINLINE unsigned int bitscan_reverse_clear_uint(unsigned int *a);
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/* NOTE: Those functions returns 2 to the power of index of highest order bit. */
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MINLINE unsigned int highest_order_bit_uint(unsigned int n);
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MINLINE unsigned short highest_order_bit_s(unsigned short n);
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#if COMPILER_GCC || COMPILER_CLANG
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# define count_bits_i(i) __builtin_popcount(i)
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# define count_bits_uint64(i) __builtin_popcountll(i)
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#elif COMPILER_MSVC
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# define count_bits_i(i) __popcnt(i)
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# define count_bits_uint64(i) __popcnt64(i)
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#else
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MINLINE int count_bits_i(unsigned int n);
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MINLINE int count_bits_uint64(uint64_t a);
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#endif
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MINLINE int float_as_int(float f);
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MINLINE unsigned int float_as_uint(float f);
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MINLINE float int_as_float(int i);
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MINLINE float uint_as_float(unsigned int i);
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MINLINE float xor_fl(float x, int y);
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MINLINE float half_to_float(ushort h);
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#if BLI_MATH_DO_INLINE
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# include "intern/math_bits_inline.c"
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#endif
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#ifdef __cplusplus
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}
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#endif
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