diff --git a/libcxx/include/string b/libcxx/include/string --- a/libcxx/include/string +++ b/libcxx/include/string @@ -1421,21 +1421,20 @@ _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type copy(value_type* __s, size_type __n, size_type __pos = 0) const; - // TODO: Maybe don't pass in the allocator. See https://llvm.org/PR57190 #if _LIBCPP_STD_VER <= 20 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string substr(size_type __pos = 0, size_type __n = npos) const { - return basic_string(*this, __pos, __n, __alloc()); + return basic_string(*this, __pos, __n); } #else _LIBCPP_HIDE_FROM_ABI constexpr basic_string substr(size_type __pos = 0, size_type __n = npos) const& { - return basic_string(*this, __pos, __n, __alloc()); + return basic_string(*this, __pos, __n); } _LIBCPP_HIDE_FROM_ABI constexpr basic_string substr(size_type __pos = 0, size_type __n = npos) && { - return basic_string(std::move(*this), __pos, __n, __alloc()); + return basic_string(std::move(*this), __pos, __n); } #endif diff --git a/libcxx/test/std/strings/basic.string/string.cons/substr.allocator.pass.cpp b/libcxx/test/std/strings/basic.string/string.cons/substr.allocator.pass.cpp new file mode 100644 --- /dev/null +++ b/libcxx/test/std/strings/basic.string/string.cons/substr.allocator.pass.cpp @@ -0,0 +1,47 @@ +//===----------------------------------------------------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +#include + +#include "test_allocator.h" +#include "test_macros.h" + +TEST_CONSTEXPR_CXX20 bool test() { + { + using alloc = test_allocator; + using string = std::basic_string, alloc>; + test_allocator_statistics stats; + { + string str((alloc(&stats))); + // Before C++17 the above constructor call may generate a call to the move constructor of the allocator + stats = test_allocator_statistics(); + (void)str.substr(); + assert(stats.moved == 0); + assert(stats.copied == 0); + } + { + string str((alloc(&stats))); + // Before C++17 the above constructor call may generate a call to the move constructor of the allocator + stats = test_allocator_statistics(); + (void)std::move(str).substr(); + assert(stats.moved == 0); + assert(stats.copied == 0); + } + } + + return true; +} + +int main(int, char**) { + test(); +#if TEST_STD_VER >= 20 + static_assert(test()); +#endif + + return 0; +}