Should it be possible to use long long?

[jszuppe]

File test/libclcxx/pipes/TestBasicPipeStructData.cl (OpenCL 2.2 C++) from libclcxx tests contains a structure which contains a long long member. If you compile that file as describled in the readme there are no errors. If later you translate binary .spir file to text SPIR-V .spt file (using llvm-spirv or spirv-dis), it turns out that there is a TypeInt <id> 128 0 SPIR-V instruction, which defines a 128-bit integer.

That means that not only OpenCL C++ compiler accepted long long type, which is not defined in OpenCL C++ spec (however, long long is a reserved for future use), but also compiled it to 128-bit integer (I would somehow understand if it compiles long long to 64-bit integer`).

// in .cl file:
struct structType
{
    float a;
    int b;
    long long c;
};

// in .spt file:
4 TypeInt <ID> 128 0

Is it correct behaviour? Because I would expect a compilation error.

[bsochack]

I think it's a compiler bug and it should be fixed

[AlexeySotkin]

@bsochack, C++14 supports long long types, why OpenCL C++ does not ?
Anyway I think OpenCL C++ spec should be fixed too. If there is a limitation in comparison to C++ 14 spec, it must be enumerated in section 2.9 Restrictions

[jszuppe]

OpenCL C++ specification explicitly lists supported built-in scalar data types, so I am not sure if we need to add information about this in the "Restrictions" section. At the beginning of the 2nd chapter it's said that the whole chapter describes restrictions to the C++14 specification supported in OpenCL C++. Maybe we can add a general note that OpenCL C++ does not support scalar data types which are not listed in "Supported Built-in Data Types" section. What's interesting is that in OpenCL C spec t long long type is mentioned in section called "Reserved Data Types".