66adedbd78
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
83 lines
2.2 KiB
C++
83 lines
2.2 KiB
C++
/* SPDX-FileCopyrightText: 2023 Blender Authors
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*
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* SPDX-License-Identifier: Apache-2.0 */
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#include "BLI_math_bits.h"
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#include "testing/testing.h"
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#include <iostream>
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TEST(math_bits, BitscanReverseClearUint)
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{
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uint a = 1234;
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EXPECT_EQ(bitscan_reverse_clear_uint(&a), 21);
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EXPECT_EQ(a, 210);
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EXPECT_EQ(bitscan_reverse_clear_uint(&a), 24);
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EXPECT_EQ(a, 82);
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EXPECT_EQ(bitscan_reverse_clear_uint(&a), 25);
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EXPECT_EQ(a, 18);
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EXPECT_EQ(bitscan_reverse_clear_uint(&a), 27);
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EXPECT_EQ(a, 2);
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EXPECT_EQ(bitscan_reverse_clear_uint(&a), 30);
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EXPECT_EQ(a, 0);
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a = 3563987529;
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EXPECT_EQ(bitscan_reverse_clear_uint(&a), 0);
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EXPECT_EQ(a, 1416503881);
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EXPECT_EQ(bitscan_reverse_clear_uint(&a), 1);
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EXPECT_EQ(a, 342762057);
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EXPECT_EQ(bitscan_reverse_clear_uint(&a), 3);
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EXPECT_EQ(a, 74326601);
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EXPECT_EQ(bitscan_reverse_clear_uint(&a), 5);
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EXPECT_EQ(a, 7217737);
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EXPECT_EQ(bitscan_reverse_clear_uint(&a), 9);
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EXPECT_EQ(a, 3023433);
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EXPECT_EQ(bitscan_reverse_clear_uint(&a), 10);
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EXPECT_EQ(a, 926281);
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EXPECT_EQ(bitscan_reverse_clear_uint(&a), 12);
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EXPECT_EQ(a, 401993);
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EXPECT_EQ(bitscan_reverse_clear_uint(&a), 13);
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EXPECT_EQ(a, 139849);
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EXPECT_EQ(bitscan_reverse_clear_uint(&a), 14);
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EXPECT_EQ(a, 8777);
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EXPECT_EQ(bitscan_reverse_clear_uint(&a), 18);
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EXPECT_EQ(a, 585);
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EXPECT_EQ(bitscan_reverse_clear_uint(&a), 22);
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EXPECT_EQ(a, 73);
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EXPECT_EQ(bitscan_reverse_clear_uint(&a), 25);
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EXPECT_EQ(a, 9);
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EXPECT_EQ(bitscan_reverse_clear_uint(&a), 28);
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EXPECT_EQ(a, 1);
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EXPECT_EQ(bitscan_reverse_clear_uint(&a), 31);
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EXPECT_EQ(a, 0);
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}
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TEST(math_bits, PopCount)
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{
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{
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EXPECT_EQ(count_bits_i(0), 0);
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EXPECT_EQ(count_bits_uint64(0), 0);
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}
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{
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const int value = (1 << 0) | (1 << 5) | (1 << 7);
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const int count_32 = count_bits_i(value);
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const int count_64 = count_bits_uint64(value);
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EXPECT_EQ(count_32, 3);
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EXPECT_EQ(count_64, 3);
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}
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{
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const uint64_t value = (uint64_t(1) << 0) | (uint64_t(1) << 50);
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const int count = count_bits_uint64(value);
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EXPECT_EQ(count, 2);
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}
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{
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const int value = -1;
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const int count = count_bits_i(value);
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EXPECT_EQ(count, 32);
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}
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{
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const uint64_t value = -1;
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const int count = count_bits_uint64(value);
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EXPECT_EQ(count, 64);
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}
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}
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