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add tiny_sort for 0 to 4 elements

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Brendan Hansknecht 2024-07-22 18:30:18 -07:00
parent 65ab733a63
commit 1c90e01385
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1 changed files with 83 additions and 0 deletions
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83
crates/compiler/builtins/bitcode/src/sort.zig
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@ -56,6 +56,89 @@ fn quadsort_direct(
roc_panic("todo: quadsort", 0);
}
// ================ Small Arrays ==============================================
// Below are functions for sorting 0 to 31 element arrays.
/// Sort arrays of 0 to 4 elements.
fn tiny_sort(array: [*]u8, len: usize, cmp_data: Opaque, cmp: CompareFn, element_width: usize, copy: CopyFn) void {
var buffer: [MAX_ELEMENT_BUFFER_SIZE]u8 = undefined;
const swap_ptr = @as([*]u8, @ptrCast(&buffer[0]));
switch (len) {
4 => {
var arr_ptr = array;
swap_branchless(arr_ptr, swap_ptr, cmp_data, cmp, element_width, copy);
arr_ptr += 2 * element_width;
swap_branchless(arr_ptr, swap_ptr, cmp_data, cmp, element_width, copy);
arr_ptr -= element_width;
const gt = @as(utils.Ordering, @enumFromInt(cmp(cmp_data, arr_ptr, arr_ptr + element_width))) == utils.Ordering.GT;
if (gt) {
copy(swap_ptr, arr_ptr);
copy(arr_ptr, arr_ptr + element_width);
copy(arr_ptr + element_width, swap_ptr);
arr_ptr -= element_width;
swap_branchless(arr_ptr, swap_ptr, cmp_data, cmp, element_width, copy);
arr_ptr += 2 * element_width;
swap_branchless(arr_ptr, swap_ptr, cmp_data, cmp, element_width, copy);
arr_ptr -= element_width;
swap_branchless(arr_ptr, swap_ptr, cmp_data, cmp, element_width, copy);
}
},
3 => {
var arr_ptr = array;
swap_branchless(arr_ptr, swap_ptr, cmp_data, cmp, element_width, copy);
arr_ptr += element_width;
swap_branchless(arr_ptr, swap_ptr, cmp_data, cmp, element_width, copy);
arr_ptr = array;
swap_branchless(arr_ptr, swap_ptr, cmp_data, cmp, element_width, copy);
},
2 => {
swap_branchless(array, swap_ptr, cmp_data, cmp, element_width, copy);
},
1, 0 => {
return;
},
else => {
unreachable;
},
}
}
test "tiny_sort" {
var arr = [4]i64{ 4, 2, 1, 3 };
var arr_ptr = @as([*]u8, @ptrCast(&arr[0]));
tiny_sort(arr_ptr, 4, null, &test_i64_compare, @sizeOf(i64), &test_i64_copy);
try testing.expectEqual(arr, [4]i64{ 1, 2, 3, 4 });
arr = [4]i64{ 2, 1, 4, 3 };
tiny_sort(arr_ptr, 4, null, &test_i64_compare, @sizeOf(i64), &test_i64_copy);
try testing.expectEqual(arr, [4]i64{ 1, 2, 3, 4 });
arr = [4]i64{ 2, 3, 1, -1 };
tiny_sort(arr_ptr, 3, null, &test_i64_compare, @sizeOf(i64), &test_i64_copy);
try testing.expectEqual(arr, [4]i64{ 1, 2, 3, -1 });
arr = [4]i64{ 2, 1, -1, -1 };
tiny_sort(arr_ptr, 2, null, &test_i64_compare, @sizeOf(i64), &test_i64_copy);
try testing.expectEqual(arr, [4]i64{ 1, 2, -1, -1 });
}
// ================ Primitives ================================================
// Below are sorting primitives that attempt to be branchless.
// They all also are always inline for performance.
// The are the smallest fundamental unit.
/// Merge two neighboring sorted 4 element arrays into swap.
inline fn parity_merge_four(ptr: [*]u8, swap: [*]u8, cmp_data: Opaque, cmp: CompareFn, element_width: usize, copy: CopyFn) void {
var left = ptr;