b8f6f9e741
Currently, unary expressions involving valarray will create a temporary. This leads to dangling references in expressions like `-a * b`, because `-a` is a temporary and the resulting expression will refer to it. This patch fixes the problem by creating a lazy expression to perform the unary operation instead of eagerly creating a temporary valarray. This is permitted by the Standard, which does not specify the exact type of most expressions involving valarrays. This is technically an ABI break, however I believe the actual potential for breakage is very low. rdar://90152242 Differential Revision: https://reviews.llvm.org/D125019
55 lines
1.6 KiB
C++
55 lines
1.6 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// <valarray>
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// template<class T> class valarray;
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// valarray<bool> operator!() const;
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#include <valarray>
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#include <cassert>
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#include <cstddef>
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#include "test_macros.h"
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int main(int, char**)
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{
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{
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typedef int T;
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T a[] = {1, 2, 3, 4, 5};
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const unsigned N = sizeof(a)/sizeof(a[0]);
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std::valarray<T> v(a, N);
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std::valarray<bool> v2 = !v;
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assert(v2.size() == v.size());
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for (std::size_t i = 0; i < v2.size(); ++i)
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assert(v2[i] == !v[i]);
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}
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{
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typedef double T;
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T a[] = {1, 2.5, 3, 4.25, 5};
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const unsigned N = sizeof(a)/sizeof(a[0]);
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std::valarray<T> v(a, N);
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std::valarray<bool> v2 = !(v + v);
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assert(v2.size() == v.size());
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for (std::size_t i = 0; i < v2.size(); ++i)
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assert(v2[i] == !(v[i] + v[i]));
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}
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{
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// Make sure we don't have dangling reference problems with unary expressions
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bool array[] = {true, false, true};
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std::valarray<bool> a(array, 3);
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std::valarray<bool> b(array, 3);
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auto c = !a && b;
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assert(c.size() == 3);
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assert(c[0] == false && c[1] == false && c[2] == false);
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}
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return 0;
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}
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