Robert Nystrom
2034061433
Change-Id: I313a57ed7c7ea2ada75065f55a7367376f6bdae5 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/152183 Commit-Queue: Bob Nystrom <rnystrom@google.com> Auto-Submit: Bob Nystrom <rnystrom@google.com> Reviewed-by: Srujan Gaddam <srujzs@google.com>
37 lines
1.2 KiB
Dart
37 lines
1.2 KiB
Dart
// Copyright (c) 2017, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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//
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// Check that optimizer correctly handles (x << y) & MASK_32 pattern on 32-bit
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// platforms: given the pattern
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//
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// v1 <- UnboxedIntConverter([tr] mint->uint32, v0)
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// v2 <- UnboxedIntConverter(uint32->mint, v1)
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//
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// optimizer must *not* replace v2 with v0 because the first conversion is
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// truncating and is erasing the high part of the mint value.
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//
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// VMOptions=--optimization-counter-threshold=5 --no-background-compilation
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import "package:expect/expect.dart";
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const _MASK_32 = 0xffffffff;
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int _rotl32(int val, int shift) {
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final mod_shift = shift & 31;
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return ((val << mod_shift) & _MASK_32) |
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((val & _MASK_32) >> (32 - mod_shift));
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}
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rot8(v) => _rotl32(v, 8);
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main() {
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// Note: value is selected in such a way that (value << 8) is not a smi - this
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// triggers emission of BinaryMintOp instructions for shifts.
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const value = 0xF0F00000;
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const rotated = 0xF00000F0;
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Expect.equals(rotated, rot8(value));
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for (var i = 0; i < 10; i++) {
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Expect.equals(rotated, rot8(value));
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}
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}
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