On Wed, 17 Dec 2025 at 21:10, Jonathan Wakely <[email protected]> wrote:
>
> On Wed, 17 Dec 2025 at 20:52, Luc Grosheintz <[email protected]> wrote:
> >
> > On Solaris, same_as<int8_t, char> is true. Therefore, int8_t isn't a
> > valid IndexType, because char is neither a signed nor an unsigned
> > integer type.
> >
> > This commit fixes the tests by avoiding int8_t (and uint8_t) by using
> > 'signed char' (and 'unsigned char').
> >
> > PR libstdc++/123176
> >
> > libstdc++-v3/ChangeLog:
> >
> > *
> > testsuite/23_containers/mdspan/submdspan/submdspan_canonicalize_slices_neg.cc:
> > Avoid
> > int8_t with signed char.
> >
> > Signed-off-by: Luc Grosheintz <[email protected]>
> > ---
> >
> > This fix is purely based on a theoretical understanding of the compiler
> > messages reported in the bug report. Unfortunately, I don't have access
> > to a Solaris machine; and therefore am not able to test on Solaris. I
> > have tested on linux-x86_64.
> >
> > I've CC'ed Rainer Orth who reported the issue, maybe Rainer's willing
> > and has time to test it on Solaris.
> >
> > .../submdspan_canonicalize_slices_neg.cc | 32 +++++++++++--------
> > 1 file changed, 18 insertions(+), 14 deletions(-)
> >
> > diff --git
> > a/libstdc++-v3/testsuite/23_containers/mdspan/submdspan/submdspan_canonicalize_slices_neg.cc
> >
> > b/libstdc++-v3/testsuite/23_containers/mdspan/submdspan/submdspan_canonicalize_slices_neg.cc
> > index 94bca183aa3..0098547d750 100644
> > ---
> > a/libstdc++-v3/testsuite/23_containers/mdspan/submdspan/submdspan_canonicalize_slices_neg.cc
> > +++
> > b/libstdc++-v3/testsuite/23_containers/mdspan/submdspan/submdspan_canonicalize_slices_neg.cc
> > @@ -8,9 +8,12 @@ constexpr size_t dyn = std::dynamic_extent;
> > constexpr auto dyn_empty = std::extents<int32_t, dyn>{0};
> > constexpr auto sta_empty = std::extents<uint32_t, 0>{};
> >
> > -constexpr auto dyn_uexts = std::extents<uint8_t, dyn>{5};
> > +// On Solaris same_as<int8_t, char> is true. Therefore, int8_t is not a
> > signed
> > +// or unsigned integer type and hence not a valid IndexType. We'll use
> > signed
> > +// char and unsigned char for int8_t throughout.
> > +constexpr auto dyn_uexts = std::extents<unsigned char, dyn>{5};
> > constexpr auto sta_uexts = std::extents<uint16_t, 5>{5};
> > -constexpr auto dyn_sexts = std::extents<int8_t, dyn>{5};
> > +constexpr auto dyn_sexts = std::extents<signed char, dyn>{5};
> > constexpr auto sta_sexts = std::extents<int16_t, 5>{5};
> >
> > constexpr bool
> > @@ -69,7 +72,7 @@ template<typename Offset, typename Extent, typename
> > Stride, typename Extents>
> > return true;
> > }
> >
> > -constexpr auto i8_1 = int8_t{1};
> > +constexpr auto i8_1 = (signed char){1};
> >
> > static_assert(test_under2(-i8_1, 0, 1, dyn_uexts)); // { dg-error
> > "expansion of" }
> > static_assert(test_under2(0, -i8_1, 1, dyn_uexts)); // { dg-error
> > "expansion of" }
> > @@ -84,7 +87,7 @@ static_assert(test_under2(-i8_1, 0, 1, sta_sexts)); //
> > { dg-error "expansion o
> > static_assert(test_under2(0, -i8_1, 1, sta_sexts)); // { dg-error
> > "expansion of" }
> > static_assert(test_under2(0, 1, -i8_1, sta_sexts)); // { dg-error
> > "expansion of" }
> >
> > -constexpr auto c_i8_m1 = std::cw<int8_t{-1}>;
> > +constexpr auto c_i8_m1 = std::cw<(signed char){-1}>;
> > constexpr auto c_i16_m1 = std::cw<int16_t{-1}>;
> > constexpr auto c_i64_m1 = std::cw<int64_t{-1}>;
> >
> > @@ -109,8 +112,8 @@ template<typename Offset, typename Extent, typename
> > Stride, typename Extents>
> > return true;
> > }
> >
> > -constexpr auto i8_6 = int8_t{6};
> > -constexpr auto c_i8_6 = std::cw<int8_t{6}>;
> > +constexpr auto i8_6 = (signed char){6};
> > +constexpr auto c_i8_6 = std::cw<(signed char){6}>;
>
> Actually all these braces should be removed, so just:
>
> (signed char){6} not (signed char){6}, otherwise it's a C99 compound
> literal, which is not valid in C++ and will warn with -pedantic.
Gah, pasted the wrong thing. I mean:
(signed char)6 not (signed char){6}
>
>
> > constexpr auto c2 = std::cw<2>;
> > constexpr auto c4 = std::cw<4>;
> >
> > @@ -155,21 +158,22 @@ static_assert(test_over2(c2, c4, 1, sta_sexts));
> > // { dg-error "expansion of
> > constexpr bool
> > test_overflow1(auto o, auto e)
> > {
> > - auto exts = std::extents<uint8_t, dyn>{255};
> > + auto exts = std::extents<unsigned char,
> > dyn>{std::numeric_limits<unsigned char>::max()};
> > auto slice = std::strided_slice{o, e, 1};
> > std::submdspan_canonicalize_slices(exts, slice);
> > return true;
> > }
> >
> > -static_assert(test_overflow1(128, 128)); // { dg-error
> > "expansion of" }
> > -static_assert(test_overflow1(std::cw<128>, 128)); // { dg-error
> > "expansion of" }
> > -static_assert(test_overflow1(128, std::cw<128>)); // { dg-error
> > "expansion of" }
> > -static_assert(test_overflow1(std::cw<128>, std::cw<128>)); // { dg-error
> > "expansion of" }
> > +constexpr int half_max = std::numeric_limits<unsigned char>::max() / 2 + 1;
> > +static_assert(test_overflow1(half_max, half_max)); // {
> > dg-error "expansion of" }
> > +static_assert(test_overflow1(std::cw<half_max>, half_max)); // {
> > dg-error "expansion of" }
> > +static_assert(test_overflow1(half_max, std::cw<half_max>)); // {
> > dg-error "expansion of" }
> > +static_assert(test_overflow1(std::cw<half_max>, std::cw<half_max>)); // {
> > dg-error "expansion of" }
> >
> > constexpr bool
> > test_overflow2(auto b, auto e)
> > {
> > - auto exts = std::extents<uint8_t, dyn>{255};
> > + auto exts = std::extents<unsigned char,
> > dyn>{std::numeric_limits<unsigned char>::max()};
> > auto slice = std::pair{b, e};
> > std::submdspan_canonicalize_slices(exts, slice);
> > return true;
> > @@ -180,8 +184,8 @@ static_assert(test_overflow2(std::cw<5>, 4));
> > // { dg-error "expansion
> > static_assert(test_overflow2(5, std::cw<4>)); // { dg-error
> > "expansion of" }
> > static_assert(test_overflow2(std::cw<5>, std::cw<4>)); // { dg-error
> > "expansion of" }
> >
> > -constexpr auto u8_4 = uint8_t{4};
> > -constexpr auto u8_5 = uint8_t{5};
> > +constexpr auto u8_4 = (unsigned char){4};
> > +constexpr auto u8_5 = (unsigned char){5};
> > static_assert(test_overflow2(u8_5, u8_4)); // {
> > dg-error "expansion of" }
> > static_assert(test_overflow2(std::cw<u8_5>, u8_4)); // {
> > dg-error "expansion of" }
> > static_assert(test_overflow2(u8_5, std::cw<u8_4>)); // {
> > dg-error "expansion of" }
> > --
> > 2.52.0
> >
