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[libc++][vector<bool>] Tests shrink_to_fit requirement. #98009
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@llvm/pr-subscribers-libcxx Author: Mark de Wever (mordante) Changesvector<bool>'s shrink_to_fit implementation is using the "swap-to-free-container-resources-trick" which only shrinks when the input vector is empty. Since the request to shrink_to_fit is non-binding, this is a valid implementation. It is not a high-quality implementation. Since vector<bool> is not a very popular container the implementation has not been changed and only a test to validate the non-growing property has been added. This was discovered while investigating #95161 Full diff: https://github.com/llvm/llvm-project/pull/98009.diff 1 Files Affected:
diff --git a/libcxx/test/std/containers/sequences/vector.bool/shrink_to_fit.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/shrink_to_fit.pass.cpp
index b39245cab7bf4..4c1c1c68ed1aa 100644
--- a/libcxx/test/std/containers/sequences/vector.bool/shrink_to_fit.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/shrink_to_fit.pass.cpp
@@ -39,9 +39,46 @@ TEST_CONSTEXPR_CXX20 bool tests()
return true;
}
+#if TEST_STD_VER >= 23
+std::size_t min_bytes = 1000;
+
+template <typename T>
+struct increasing_allocator {
+ using value_type = T;
+ increasing_allocator() = default;
+ template <typename U>
+ increasing_allocator(const increasing_allocator<U>&) noexcept {}
+ std::allocation_result<T*> allocate_at_least(std::size_t n) {
+ std::size_t allocation_amount = n * sizeof(T);
+ if (allocation_amount < min_bytes)
+ allocation_amount = min_bytes;
+ min_bytes += 1000;
+ return {static_cast<T*>(::operator new(allocation_amount)), allocation_amount / sizeof(T)};
+ }
+ T* allocate(std::size_t n) { return allocate_at_least(n).ptr; }
+ void deallocate(T* p, std::size_t) noexcept { ::operator delete(static_cast<void*>(p)); }
+};
+
+template <typename T, typename U>
+bool operator==(increasing_allocator<T>, increasing_allocator<U>) {
+ return true;
+}
+
+// https://github.com/llvm/llvm-project/issues/95161
+void test_increasing_allocator() {
+ std::vector<bool, increasing_allocator<bool>> v;
+ v.push_back(1);
+ std::size_t capacity = v.capacity();
+ v.shrink_to_fit();
+ assert(v.capacity() <= capacity);
+ assert(v.size() == 1);
+}
+#endif // TEST_STD_VER >= 23
+
int main(int, char**)
{
tests();
+ test_increasing_allocator();
#if TEST_STD_VER > 17
static_assert(tests());
#endif
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libcxx/test/std/containers/sequences/vector.bool/shrink_to_fit.pass.cpp
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vector<bool>'s shrink_to_fit implementation is using the "swap-to-free-container-resources-trick" which only shrinks when the input vector is empty. Since the request to shrink_to_fit is non-binding, this is a valid implementation. It is not a high-quality implementation. Since vector<bool> is not a very popular container the implementation has not been changed and only a test to validate the non-growing property has been added. This was discovered while investigating llvm#95161
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/cherry-pick c2e4386 |
`vector<bool>`'s shrink_to_fit implementation is using the "swap-to-free-container-resources-trick" which only shrinks when the input vector is empty. Since the request to shrink_to_fit is non-binding, this is a valid implementation. It is not a high-quality implementation. Since `vector<bool>` is not a very popular container the implementation has not been changed and only a test to validate the non-growing property has been added. This was discovered while investigating llvm#95161. (cherry picked from commit c2e4386)
/pull-request #100145 |
`vector<bool>`'s shrink_to_fit implementation is using the "swap-to-free-container-resources-trick" which only shrinks when the input vector is empty. Since the request to shrink_to_fit is non-binding, this is a valid implementation. It is not a high-quality implementation. Since `vector<bool>` is not a very popular container the implementation has not been changed and only a test to validate the non-growing property has been added. This was discovered while investigating llvm#95161.
`vector<bool>`'s shrink_to_fit implementation is using the "swap-to-free-container-resources-trick" which only shrinks when the input vector is empty. Since the request to shrink_to_fit is non-binding, this is a valid implementation. It is not a high-quality implementation. Since `vector<bool>` is not a very popular container the implementation has not been changed and only a test to validate the non-growing property has been added. This was discovered while investigating llvm#95161. (cherry picked from commit c2e4386)
Summary: `vector<bool>`'s shrink_to_fit implementation is using the "swap-to-free-container-resources-trick" which only shrinks when the input vector is empty. Since the request to shrink_to_fit is non-binding, this is a valid implementation. It is not a high-quality implementation. Since `vector<bool>` is not a very popular container the implementation has not been changed and only a test to validate the non-growing property has been added. This was discovered while investigating #95161. Test Plan: Reviewers: Subscribers: Tasks: Tags: Differential Revision: https://phabricator.intern.facebook.com/D60251031
vector<bool>
's shrink_to_fit implementation is using the "swap-to-free-container-resources-trick" which only shrinks when the input vector is empty. Since the request to shrink_to_fit is non-binding, this is a valid implementation. It is not a high-quality implementation. Sincevector<bool>
is not a very popular container the implementation has not been changed and only a test to validate the non-growing property has been added.This was discovered while investigating #95161