Problem using TBB 2020.3 with Intel icx 2023.1 on Windows trying to use concurrent_hash_map::emplace

[jamesrburgess]

The VFX reference platform for 2023 and later is still on this older branch of tbb and I'm wanting to use that with the latest icx compiler. In tbb_config.h on Windows, we drop into the __clang__ section and the detection of whether rvalue references goes awry because we are neither using libc++ nor glibc on Windows. This then disables the emplace method.

Here is the relevant section in tbb/tbb_config.h:

#elif __clang__
/** TODO: these options need to be rechecked **/
    ...
    #define __TBB_CPP11_RVALUE_REF_PRESENT                  (__has_feature(__cxx_rvalue_references__) && (_LIBCPP_VERSION || __TBB_GLIBCXX_VERSION >= 40500))

and you can see that __TBB_CPP11_RVALUE_REF_PRESENT is going to come out as zero even though __has_feature(__cxx_rvalue_references__) will return 1.

A few lines down in the same __clang__ section we see std::begin and end are also disabled for the same reason.

Not knowing precisely why libc++ and glibc come into this calculation I could not confidently suggest a solution, but in my instance, which I think would be fairly broad I can modify both of those lines to use the following:

    #define __TBB_CPP11_RVALUE_REF_PRESENT                  (__has_feature(__cxx_rvalue_references__) && (_LIBCPP_VERSION || __TBB_GLIBCXX_VERSION >= 40500 || _MSC_VER >= 1916))

so enable if clang, has rvalue references, and is on Windows with Visual Studio 2019 or better compiler.

[isaevil]

Hi, I can't surely tell for the TBB 2020 but it seems that it just wasn't intended to fall under __clang__ branch on Windows, but since icx is LLVM-based we do. I think your code change is valid.

Notify: @pavelkumbrasev

[pavelkumbrasev]

The problem is that development of TBB (with last official version - 2020.U3) was stopped before icx (LLVM based Intel compiler) was released so that's why we can observe such issues.
On a first glance this solution can be used as a workaround.

[nofuturre]

@jamesrburgess is this issue still relevant?

[nofuturre]

If anyone encounter this issue in the future please open new issue with a link to this one

[jamesrburgess]

We're shipping code with my patch. Seems to work. I'm trying hard to get us off of 2020.U3 still :-)