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Date: Tue, 7 Jul 2026 12:18:31 +0200 Message-ID: <20260707102055.512253-1-tkaminsk@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: CgMnUQ7RdDmeRregD2mKH3JgULivugK781Rr0ytzgtA_1783419658 X-Mimecast-Originator: redhat.com content-type: text/plain; charset="US-ASCII"; x-default=true X-Spam-Status: No, score=-10.8 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL, RCVD_IN_SBL_CSS, SPF_HELO_PASS, SPF_NONE, TXREP shortcircuit=no autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on sourceware.org X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: gcc-patches-bounces~patchwork=sourceware.org@gcc.gnu.org Converting the __strides values using __index_type_cast asserts that they are non-negative and each value is representable as index_type. libstdc++-v3/ChangeLog: * include/std/mdspan (layout_stride::mapping::mapping(const extent_type&, span<...>): Convert strides using __index_type_cast, which bring asserts for negative and unrepresentable values. * testsuite/23_containers/mdspan/layouts/stride_neg.cc: New test. --- Tested on x86_64-linux locally. OK for trunk? libstdc++-v3/include/std/mdspan | 3 +- .../mdspan/layouts/stride_neg.cc | 31 +++++++++++++++++++ 2 files changed, 33 insertions(+), 1 deletion(-) create mode 100644 libstdc++-v3/testsuite/23_containers/mdspan/layouts/stride_neg.cc diff --git a/libstdc++-v3/include/std/mdspan b/libstdc++-v3/include/std/mdspan index f5556f35fa1..5e1c4d8b1a4 100644 --- a/libstdc++-v3/include/std/mdspan +++ b/libstdc++-v3/include/std/mdspan @@ -1891,7 +1891,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION : _M_extents(__exts) { for (size_t __i = 0; __i < extents_type::rank(); ++__i) - _M_strides[__i] = index_type(as_const(__strides[__i])); + _M_strides[__i] + = __mdspan::__index_type_cast(__strides[__i]); } template diff --git a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/stride_neg.cc b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/stride_neg.cc new file mode 100644 index 00000000000..153560bc82f --- /dev/null +++ b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/stride_neg.cc @@ -0,0 +1,31 @@ +// { dg-do compile { target c++23 } } +#include + +#include "../layout_traits.h" +#include + +constexpr size_t dyn = std::dynamic_extent; + +constexpr bool +test_stride_overflow() +{ + auto exts = std::extents(1, 3); + auto n = size_t(1) << 9; + auto m = std::layout_stride::mapping(exts, std::array{n, 1zu}); // { dg-error "expansion of" } + (void) m; + return true; +} +static_assert(test_stride_overflow()); // { dg-error "expansion of" } + +constexpr bool +test_stride_negative() +{ + auto exts = std::extents(1, 3); + auto m = std::layout_stride::mapping(exts, std::array{1, -4}); // { dg-error "expansion of" } + (void) m; + return true; +} +static_assert(test_stride_negative()); // { dg-error "expansion of" } + +// { dg-prune-output "non-constant condition for static assertion" } +// { dg-prune-output "__glibcxx_assert_fail()" }