Compiling with icpc

[tdegeus]

I would like to compile with the Intel C++ compiler, in particular this one

$ icpc --version
icpc (ICC) 17.0.2 20170213
Copyright (C) 1985-2017 Intel Corporation.  All rights reserved.

But currently this results in

...json.hpp(67): error: #error directive: "unsupported GCC version - see https://github.com/nlohmann/json#supported-compilers"
          #error "unsupported GCC version - see https://github.com/nlohmann/json#supported-compilers"

When I remove the checks, I'm able to successfully compile and run. Compiling with -Wall -Wextra -pendantic only results in the following warnings

/home/tdegeus/prog/research/avalanches_inertia/json/json.hpp(6323): warning #186: pointless comparison of unsigned integer with zero
          return ((0 <= u and u <= 127) ? 0
                     ^
          detected during:
            instantiation of "std::size_t={unsigned long} nlohmann::detail::serializer<BasicJsonType>::extra_space(const nlohmann::detail::serializer<BasicJsonType>::string_t &, bool) [with BasicJsonType=nlohmann::basic_json<std::map, std::vector, std::string, bool, int64_t={long}, uint64_t={unsigned long}, double, std::allocator, nlohmann::adl_serializer>]" at line 6500
            instantiation of "void nlohmann::detail::serializer<BasicJsonType>::dump_escaped(const nlohmann::detail::serializer<BasicJsonType>::string_t &, bool) const [with BasicJsonType=nlohmann::basic_json<std::map, std::vector, std::string, bool, int64_t={long}, uint64_t={unsigned long}, double, std::allocator, nlohmann::adl_serializer>]" at line 6154
            instantiation of "void nlohmann::detail::serializer<BasicJsonType>::dump(const BasicJsonType &, bool, bool, unsigned int, unsigned int) [with BasicJsonType=nlohmann::basic_json<std::map, std::vector, std::string, bool, int64_t={long}, uint64_t={unsigned long}, double, std::allocator, nlohmann::adl_serializer>]" at line 8995
            instantiation of "nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer>::string_t nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer>::dump(int, char, bool) const [with ObjectType=std::map, ArrayType=std::vector, StringType=std::string, BooleanType=bool,
                      NumberIntegerType=int64_t={long}, NumberUnsignedType=uint64_t={unsigned long}, NumberFloatType=double, AllocatorType=std::allocator, JSONSerializer=nlohmann::adl_serializer]" at line 14653

/home/tdegeus/prog/research/avalanches_inertia/json/json.hpp(6663): warning #186: pointless comparison of unsigned integer with zero
          const bool is_negative = x < 0;
                                     ^
          detected during:
            instantiation of "void nlohmann::detail::serializer<BasicJsonType>::dump_integer(NumberType) [with BasicJsonType=nlohmann::basic_json<std::map, std::vector, std::string, bool, int64_t={long}, uint64_t={unsigned long}, double, std::allocator, nlohmann::adl_serializer>, NumberType=uint64_t={unsigned long}, <unnamed>=0]" at line 6290
            instantiation of "void nlohmann::detail::serializer<BasicJsonType>::dump(const BasicJsonType &, bool, bool, unsigned int, unsigned int) [with BasicJsonType=nlohmann::basic_json<std::map, std::vector, std::string, bool, int64_t={long}, uint64_t={unsigned long}, double, std::allocator, nlohmann::adl_serializer>]" at line 8995
            instantiation of "nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer>::string_t nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer>::dump(int, char, bool) const [with ObjectType=std::map, ArrayType=std::vector, StringType=std::string, BooleanType=bool,
                      NumberIntegerType=int64_t={long}, NumberUnsignedType=uint64_t={unsigned long}, NumberFloatType=double, AllocatorType=std::allocator, JSONSerializer=nlohmann::adl_serializer]" at line 14653

/home/tdegeus/prog/research/avalanches_inertia/json/json.hpp(9762): warning #191: type qualifier is meaningless on cast type
          return get_impl_ptr(static_cast<const PointerType>(nullptr));
                                          ^
          detected during:
            instantiation of "void nlohmann::detail::get_arithmetic_value(const BasicJsonType &, ArithmeticType &) [with BasicJsonType=nlohmann::basic_json<std::map, std::vector, std::string, bool, int64_t={long}, uint64_t={unsigned long}, double, std::allocator, nlohmann::adl_serializer>, ArithmeticType=double, <unnamed>=0]" at line 1133
            instantiation of "void nlohmann::detail::from_json(const BasicJsonType &, BasicJsonType::number_float_t &) [with BasicJsonType=nlohmann::basic_json<std::map, std::vector, std::string, bool, int64_t={long}, uint64_t={unsigned long}, double, std::allocator, nlohmann::adl_serializer>]" at line 1368
            instantiation of "auto nlohmann::detail::from_json_fn::call(const BasicJsonType &, T &, nlohmann::detail::priority_tag<1U>) const->decltype((<expression>)) [with BasicJsonType=nlohmann::basic_json<std::map, std::vector, std::string, bool, int64_t={long}, uint64_t={unsigned long}, double, std::allocator, nlohmann::adl_serializer>, T=double]" at line 1383
            instantiation of "void nlohmann::detail::from_json_fn::operator()(const BasicJsonType &, T &) const [with BasicJsonType=nlohmann::basic_json<std::map, std::vector, std::string, bool, int64_t={long}, uint64_t={unsigned long}, double, std::allocator, nlohmann::adl_serializer>, T=double]" at line 6880
            instantiation of "void nlohmann::adl_serializer<<unnamed>, <unnamed>>::from_json(BasicJsonType &&, ValueType &) [with <unnamed>=double, <unnamed>=void, BasicJsonType=const nlohmann::basic_json<std::map, std::vector, std::string, bool, int64_t={long}, uint64_t={unsigned long}, double, std::allocator, nlohmann::adl_serializer> &, ValueType=double]" at line 9592
            instantiation of "ValueType nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer>::get<ValueTypeCV,ValueType,<unnamed>>() const [with ObjectType=std::map, ArrayType=std::vector, StringType=std::string, BooleanType=bool, NumberIntegerType=int64_t={long}, NumberUnsignedType=uint64_t={unsigned long}, NumberFloatType=double, AllocatorType=std::allocator,
                      JSONSerializer=nlohmann::adl_serializer, ValueTypeCV=double, ValueType=double, <unnamed>=0]" at line 237 of "/home/tdegeus/prog/research/avalanches_inertia/main.cpp"

remark #11074: Inlining inhibited by limit max-size
remark #11074: Inlining inhibited by limit max-total-size
remark #11076: To get full report use -qopt-report=4 -qopt-report-phase ipo

[nlohmann]

Thanks for reporting! I shall have a look at the warnings.

Apparently, we seem to "recognize" a GCC here. Could you please post the output of the json::meta() function? If the Intel Compiler is correctly recognized there, I may have an idea how to fix the compiler detection above.

[tdegeus]

Here is the output of json::meta():

{
    "compiler": {
        "c++": "201103",
        "family": "icc",
        "version": 1700
    },
    "copyright": "(C) 2013-2017 Niels Lohmann",
    "name": "JSON for Modern C++",
    "platform": "linux",
    "url": "https://github.com/nlohmann/json",
    "version": {
        "major": 2,
        "minor": 1,
        "patch": 1,
        "string": "2.1.1"
    }
}

[nlohmann]

Thanks! I shall have a look. I maybe just need to exclude ICC from the GCC version check.

By the way: do you know whether there is a free version of ICC so that I could use it in the CI test suite?

[tdegeus]

Yes, there are 'free' versions for students, academic researchers, and open-source developers.

[nlohmann]

@tdegeus All but 1 warnings should be gone now. I tried to fix the last one, but ran into a compiler issue, see #761. Could you try the latest develop version please?

[tdegeus]

@nlohmann Great, thanks! I have compiled with the latest develop version. It works. As predicted the only compiler warning that remains is

...json/json.hpp(6663): warning #186: pointless comparison of unsigned integer with zero
          const bool is_negative = x < 0;
                                     ^
          detected during:
            instantiation of "void nlohmann::detail::serializer<BasicJsonType>::dump_integer(NumberType) [with BasicJsonType=nlohmann::basic_json<std::map, std::vector, std::string, bool, int64_t={long}, uint64_t={unsigned long}, double, std::allocator, nlohmann::adl_serializer>, NumberType=uint64_t={unsigned long}, <unnamed>=0]" at line 6290
            instantiation of "void nlohmann::detail::serializer<BasicJsonType>::dump(const BasicJsonType &, bool, bool, unsigned int, unsigned int) [with BasicJsonType=nlohmann::basic_json<std::map, std::vector, std::string, bool, int64_t={long}, uint64_t={unsigned long}, double, std::allocator, nlohmann::adl_serializer>]" at line 8995
            instantiation of "nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer>::string_t nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer>::dump(int, char, bool) const [with ObjectType=std::map, ArrayType=std::vector, StringType=std::string, BooleanType=bool,
                      NumberIntegerType=int64_t={long}, NumberUnsignedType=uint64_t={unsigned long}, NumberFloatType=double, AllocatorType=std::allocator, JSONSerializer=nlohmann::adl_serializer]" at line 14655

[nlohmann]

Meanwhile, I tried to get ICC running on Travis (see https://travis-ci.org/nlohmann/json/jobs/282297971), but it fails to compile so far. Maybe someone has an idea how to fix this.

[gregmarr]

Maybe this would help:

const bool is_negative = std::is_same<NumberType, number_integer_t>::value && (x < 0);

[nlohmann]

@gregmarr Thanks!

[nlohmann]

@tdegeus Did the last change fix the last warning? If so, I would close this issue.

[tdegeus]

@nlohmann and @gregmarr Unfortunately the warning is persistent:

json.hpp(6659): warning #186: pointless comparison of unsigned integer with zero
          const bool is_negative = std::is_same<NumberType, number_integer_t>::value and (x < 0);
                                                                                            ^
          detected during:
            instantiation of "void nlohmann::detail::serializer<BasicJsonType>::dump_integer(NumberType) [with BasicJsonType=nlohmann::basic_json<std::map, std::vector, std::string, bool, int64_t={long}, uint64_t={unsigned long}, double, std::allocator, nlohmann::adl_serializer>, NumberType=uint64_t={unsigned long}, <unnamed>=0]" at line 6286
            instantiation of "void nlohmann::detail::serializer<BasicJsonType>::dump(const BasicJsonType &, bool, bool, unsigned int, unsigned int) [with BasicJsonType=nlohmann::basic_json<std::map, std::vector, std::string, bool, int64_t={long}, uint64_t={unsigned long}, double, std::allocator, nlohmann::adl_serializer>]" at line 8976
            instantiation of "nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer>::string_t nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer>::dump(int, char, bool) const [with ObjectType=std::map, ArrayType=std::vector, StringType=std::string, BooleanType=bool,
                      NumberIntegerType=int64_t={long}, NumberUnsignedType=uint64_t={unsigned long}, NumberFloatType=double, AllocatorType=std::allocator, JSONSerializer=nlohmann::adl_serializer]" at line 14636

[gregmarr]

Maybe we can fake it out a bit by doing the test in two parts:

const bool is_negative = (x <= 0) and (x != 0);

@tdegeus Can you try with that and see if it works?

[tdegeus]

@gregmarr I can confirms this fix.

I am now left with the following compiler warnings:

remark #11074: Inlining inhibited by limit max-size
remark #11074: Inlining inhibited by limit max-total-size
remark #11076: To get full report use -qopt-report=4 -qopt-report-phase ipo

[gregmarr]

Awesome. I would expect that you'll need to disable those messages on your end.

https://software.intel.com/en-us/forums/intel-c-compiler/topic/600543

[tdegeus]

Great!

(As for the Intel specific warnings. It seems that switching of the limits lets the memory usage of the compiler explode. At the moment I don't know which part of my code is most responsible. Disabling the warnings seems to be impossible in combination with keeping other compiler warnings)

[nlohmann]

Thanks everybody!

[kaidokert]

Just FYI, gcc-5.2 reports on this:

/opt/m/cbor/../ext/nlohmann _json/src/json.hpp:7047:43: error: logical 'and' of mutually exclusive tests is always false [-Werror=logical-op]
         const bool is_negative = (x <= 0) and (x != 0);  // see issue #755

[zakalibit]

I changed to this and it makes compiler happy

const bool is_negative = !(x>=0);

[TedLyngmo]

Hi! I still have this issue (although with an old unsupported clang 3.3.1 based compiler) but I managed to remove the warning by creating these templates:

    template<typename NumberType, detail::enable_if_t<
                 std::is_same<NumberType, number_unsigned_t>::value, int> = 0>
    bool is_negative_integer(NumberType x) { return false; }

    template<typename NumberType, detail::enable_if_t<
                 std::is_same<NumberType, number_integer_t>::value, int> = 0>
    bool is_negative_integer(NumberType x) { return x<0; }

and in dump_integer(NumberType x):

const bool is_negative = is_negative_integer(x); // see issue #755 

I don't know exactly where to put these templates to make a proper pull request. Right now I just put them above dump_integer() to try it out.

Would a change like this break something else? If not, can someone help me to find the proper place for the templates and I'll make a pull request out of it.