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cfeb1d647a
Change-Id: Ic9912d94e1248df70a92e2504af87d42d5ca0528 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/152617 Commit-Queue: Joshua Litt <joshualitt@google.com> Reviewed-by: Mayank Patke <fishythefish@google.com>
44 lines
1.4 KiB
Dart
44 lines
1.4 KiB
Dart
// Copyright (c) 2020, 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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/// Regression test for Issue #40349:
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///
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/// Before the fix, this code was accidentally generating a type check twice.
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/// In between the two checks, code to update `_foo` was overriding a temporary
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/// variable used by the check subexpression, which made the code for the
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/// second check invalid.
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///
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/// The second check should not have been generated, but it was emitted due to
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/// a broken invariant of the SSA generate-at-use logic.
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void main() {
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// `x` which is used multiple times after inilining, so a temporary is used.
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x.method(40);
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}
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dynamic x = Wrapper<int>();
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class A<E> {
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int _foo = 0;
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List<E?> list = [null];
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@pragma('dart2js:tryInline')
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void internalMethod(E value) {
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// The update and use of `_foo` requires a separate temporary which reuses
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// the same variable given to `x` (technically `x` is no longer live).
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_foo = (_foo + 1) & 0;
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// This use of `value` accidentally contains the second check, which
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// still refers to the temporary assuming it was `x` and not `_foo`.
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list[_foo] = value;
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}
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}
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class Wrapper<T> {
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A<T> a = A<T>();
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@pragma('dart2js:tryInline')
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method(T t) => a.internalMethod(t);
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}
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