Set

        pub const Set = struct {
            ints: [usize_count]usize,

            pub const needed_bit_count = 347;
            pub const byte_count = @divCeil(needed_bit_count, 8);
            pub const usize_count = (byte_count + (@sizeOf(usize) - 1)) / @sizeOf(usize);
            pub const Index = std.math.Log2Int(@Int(.unsigned, usize_count * @bitSizeOf(usize)));
            pub const ShiftInt = std.math.Log2Int(usize);

            pub const empty: Set = .{ .ints = @splat(0) };

            pub fn isEmpty(set: Set) bool {
                return for (set.ints) |x| {
                    if (x != 0) break false;
                } else true;
            }

            pub fn count(set: Set) std.math.IntFittingRange(0, needed_bit_count) {
                var sum: usize = 0;
                for (set.ints) |x| sum += @popCount(x);
                return @intCast(sum);
            }

            pub fn isEnabled(set: Set, arch_feature_index: Index) bool {
                const usize_index = arch_feature_index / @bitSizeOf(usize);
                const bit_index: ShiftInt = @intCast(arch_feature_index % @bitSizeOf(usize));
                return (set.ints[usize_index] & (@as(usize, 1) << bit_index)) != 0;
            }

            /// Adds the specified feature but not its dependencies.
            pub fn addFeature(set: *Set, arch_feature_index: Index) void {
                const usize_index = arch_feature_index / @bitSizeOf(usize);
                const bit_index: ShiftInt = @intCast(arch_feature_index % @bitSizeOf(usize));
                set.ints[usize_index] |= @as(usize, 1) << bit_index;
            }

            /// Adds the specified feature set but not its dependencies.
            pub fn addFeatureSet(set: *Set, other_set: Set) void {
                set.ints = @as(@Vector(usize_count, usize), set.ints) | @as(@Vector(usize_count, usize), other_set.ints);
            }

            /// Removes the specified feature but not its dependents.
            pub fn removeFeature(set: *Set, arch_feature_index: Index) void {
                const usize_index = arch_feature_index / @bitSizeOf(usize);
                const bit_index: ShiftInt = @intCast(arch_feature_index % @bitSizeOf(usize));
                set.ints[usize_index] &= ~(@as(usize, 1) << bit_index);
            }

            /// Removes the specified feature but not its dependents.
            pub fn removeFeatureSet(set: *Set, other_set: Set) void {
                set.ints = @as(@Vector(usize_count, usize), set.ints) & ~@as(@Vector(usize_count, usize), other_set.ints);
            }

            pub fn populateDependencies(set: *Set, all_features_list: []const Cpu.Feature) void {
                @setEvalBranchQuota(1000000);

                var old = set.ints;
                while (true) {
                    for (all_features_list, 0..) |feature, index_usize| {
                        const index: Index = @intCast(index_usize);
                        if (set.isEnabled(index)) {
                            set.addFeatureSet(feature.dependencies);
                        }
                    }
                    const nothing_changed = std.mem.eql(usize, &old, &set.ints);
                    if (nothing_changed) return;
                    old = set.ints;
                }
            }

            pub fn asBytes(set: *const Set) *const [byte_count]u8 {
                return std.mem.sliceAsBytes(&set.ints)[0..byte_count];
            }

            pub fn eql(set: Set, other_set: Set) bool {
                return std.mem.eql(usize, &set.ints, &other_set.ints);
            }

            pub fn isSuperSetOf(set: Set, other_set: Set) bool {
                const V = @Vector(usize_count, usize);
                const set_v: V = set.ints;
                const other_v: V = other_set.ints;
                return @reduce(.And, (set_v & other_v) == other_v);
            }
        }