| // Copyright (c) 2017, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| // |
| // Check that optimizer correctly handles (x << y) & MASK_32 pattern on 32-bit |
| // platforms: given the pattern |
| // |
| // v1 <- UnboxedIntConverter([tr] mint->uint32, v0) |
| // v2 <- UnboxedIntConverter(uint32->mint, v1) |
| // |
| // optimizer must *not* replace v2 with v0 because the first conversion is |
| // truncating and is erasing the high part of the mint value. |
| // |
| // VMOptions=--optimization-counter-threshold=90 --no-background-compilation |
| |
| import "package:expect/expect.dart"; |
| |
| const _MASK_32 = 0xffffffff; |
| int _rotl32(int val, int shift) { |
| final mod_shift = shift & 31; |
| return ((val << mod_shift) & _MASK_32) | |
| ((val & _MASK_32) >> (32 - mod_shift)); |
| } |
| |
| rot8(v) => _rotl32(v, 8); |
| |
| main() { |
| // Note: value is selected in such a way that (value << 8) is not a smi - this |
| // triggers emission of BinaryMintOp instructions for shifts. |
| const value = 0xF0F00000; |
| const rotated = 0xF00000F0; |
| Expect.equals(rotated, rot8(value)); |
| for (var i = 0; i < 100; i++) { |
| Expect.equals(rotated, rot8(value)); |
| } |
| } |
