libstdc++-v3/testsuite/23_containers/mdspan/layouts/stride_neg.cc

// { dg-do compile { target c++23 } }
#include <mdspan>
#include <cstdint>

constexpr size_t dyn = std::dynamic_extent;

constexpr bool
test_stride_overflow()
{
  auto exts = std::extents<uint8_t, dyn, dyn>(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<std::size_t, dyn, dyn>(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" } 


using std::array;
template<size_t Rank>
 using mapping = std::layout_stride::mapping<std::dextents<size_t, Rank>>;

constexpr auto m0 = mapping<0>(array<int, 0>{}, array<int, 0>{}); // { dg-bogus "expansion of" }

// Zero strides allowed for empty mappings
constexpr auto m00 = mapping<1>(array{0}, array{0}); // { dg-bogus "expansion of" }
constexpr auto m01 = mapping<2>(array{0, 1}, array{3, 0}); // { dg-bogus "expansion of" }
constexpr auto m02 = mapping<2>(array{0, 1}, array{0, 0}); // { dg-bogus "expansion of" }
constexpr auto m03 = mapping<3>(array{0, 1, 2}, array{3, 0, 0}); // { dg-bogus "expansion of" }
constexpr auto m04 = mapping<3>(array{0, 1, 2}, array{3, 3, 0}); // { dg-bogus "expansion of" }
constexpr auto m05 = mapping<4>(array{0, 1, 2, 3}, array{5, 3, 0, 2}); // { dg-bogus "expansion of" }

// Otherwise leads to non-unique mappings.
constexpr auto m06 = mapping<1>(array{1}, array{0});                   // { dg-error "expansion of" }
constexpr auto m07 = mapping<2>(array{1, 2}, array{3, 0});             // { dg-error "expansion of" } 
constexpr auto m08 = mapping<3>(array{1, 2, 3}, array{3, 3, 0});       // { dg-error "expansion of" }         
constexpr auto m09 = mapping<4>(array{1, 2, 3, 5}, array{5, 3, 0, 2}); // { dg-error "expansion of" } 

// required_span_size is smaller size of multidimensional index space
constexpr auto m10 = mapping<2>(array{3, 4}, array{2, 3}); // { dg-error "expansion of" }
constexpr auto m11 = mapping<2>(array{3, 4}, array{1, 2}); // { dg-error "expansion of" }
constexpr auto m12 = mapping<3>(array{3, 4, 5}, array{1, 3, 11}); // { dg-error "expansion of" }
constexpr auto m13 = mapping<3>(array{3, 4, 5}, array{1, 2, 12}); // { dg-error "expansion of" }
constexpr auto m14 = mapping<4>(array{3, 4, 5, 6}, array{1, 3, 12, 50}); // { dg-error "expansion of" }
constexpr auto m15 = mapping<4>(array{3, 4, 5, 6}, array{1, 3, 11, 60}); // { dg-error "expansion of" }
constexpr auto m16 = mapping<4>(array{3, 4, 5, 6}, array{1, 2, 12, 60}); // { dg-error "expansion of" }

// Passes required_span_size check (smaller and bigger stride), detected only in debug mode
constexpr auto m17 = mapping<3>(array{3, 4, 5}, array{1, 2, 25}); // { dg-error "expansion of" "" { target debug_mode } }
constexpr auto m18 = mapping<3>(array{3, 4, 5}, array{1, 5, 12}); // { dg-error "expansion of" "" { target debug_mode } }
constexpr auto m19 = mapping<4>(array{3, 4, 5, 6}, array{1, 2, 12, 100}); // { dg-error "expansion of" "" { target debug_mode } }
constexpr auto m20 = mapping<4>(array{3, 4, 5, 6}, array{1, 5, 12, 60});  // { dg-error "expansion of" "" { target debug_mode } }

// Equal indicies allowed if extents are 1
constexpr auto m21 = mapping<2>(array{5, 1}, array{1, 1}); // { dg-bogus "expansion of" }
constexpr auto m22 = mapping<3>(array{1, 5, 1}, array{1, 1, 1}); // { dg-bogus "expansion of" }
constexpr auto m23 = mapping<4>(array{1, 1, 5, 1}, array{1, 1, 1, 1}); // { dg-bogus "expansion of" }
constexpr auto m24 = mapping<5>(array{3, 4, 1, 1, 5}, array{3, 10, 3, 3, 45}); // { dg-bogus "expansion of" }
constexpr auto m25 = mapping<5>(array{3, 4, 1, 1, 5}, array{3, 10, 3, 10, 45}); // { dg-bogus "expansion of" }
constexpr auto m26 = mapping<5>(array{3, 4, 1, 1, 5}, array{3, 10, 10, 3, 45}); // { dg-bogus "expansion of" } 
constexpr auto m27 = mapping<5>(array{3, 4, 1, 1, 5}, array{3, 10, 10, 10, 45}); // { dg-bogus "expansion of" }

// Only some permutations are valid, invalid permutations detected only in debug mode.

// Unique if stride 3 corresponds to extent 3
constexpr auto m28 = mapping<2>(array{3, 4}, array{3, 10}); // { dg-bogus "expansion of" }
constexpr auto m29 = mapping<2>(array{3, 4}, array{10, 3}); // { dg-error "expansion of" "" { target debug_mode } }
constexpr auto m30 = mapping<2>(array{4, 3}, array{10, 3}); // { dg-bogus "expansion of" }
constexpr auto m31 = mapping<2>(array{4, 3}, array{3, 10}); // { dg-error "expansion of" "" { target debug_mode } }

// Unique if stride 11 corresponds to extent 3, as 11 * 3 < 35, and 2 * 5 < 11
constexpr auto m32 = mapping<3>(array{3, 4, 5}, array{11, 2, 35}); // { dg-bogus "expansion of" } 
constexpr auto m33 = mapping<3>(array{3, 4, 5}, array{11, 35, 2}); // { dg-bogus "expansion of" }
constexpr auto m34 = mapping<3>(array{3, 4, 5}, array{2, 11, 35}); // { dg-error "expansion of" "" { target debug_mode } }
constexpr auto m35 = mapping<3>(array{3, 4, 5}, array{35, 2, 11}); // { dg-error "expansion of" "" { target debug_mode } }
constexpr auto m36 = mapping<3>(array{5, 4, 3}, array{2, 35, 11}); // { dg-bogus "expansion of" }
constexpr auto m37 = mapping<3>(array{5, 4, 3}, array{2, 11, 35}); // { dg-error "expansion of" "" { target debug_mode } }
constexpr auto m38 = mapping<3>(array{5, 3, 4}, array{35, 11, 2}); // { dg-bogus "expansion of" }
constexpr auto m39 = mapping<3>(array{3, 5, 4}, array{35, 2, 11}); // { dg-error "expansion of" "" { target debug_mode } }

// Unique for stride -> extent mapping: 3 * 5 < 16, 15 * 4 < 65, 65 * 3 < 200 
constexpr auto m40 = mapping<4>(array{3, 4, 5, 6}, array{65, 16, 3, 200}); // { dg-bogus "expansion of" }
constexpr auto m41 = mapping<4>(array{3, 4, 5, 6}, array{3, 16, 65, 200}); // { dg-error "expansion of" "" { target debug_mode } } 
constexpr auto m42 = mapping<4>(array{3, 4, 5, 6}, array{200, 65, 3, 16}); // { dg-error "expansion of" "" { target debug_mode } } 
constexpr auto m43 = mapping<4>(array{5, 3, 6, 4}, array{3, 65, 200, 16}); // { dg-bogus "expansion of" }
constexpr auto m44 = mapping<4>(array{5, 3, 6, 4}, array{3, 16, 200, 65}); // { dg-error "expansion of" "" { target debug_mode } }

// { dg-prune-output "non-constant condition for static assertion" }
// { dg-prune-output "__glibcxx_assert_fail()" }