Build error with clang+mingw

[Gei0r]

When building rapidyaml (which uses fast_float) with clang+mingw on windows, I get the following error message:

FAILED: CMakeFiles/ryml.dir/src/c4/yml/tree.cpp.obj
D:\User\Adrian\Programmierung\3rdParty\rapidyaml\Clang-Windows\bin\clang++.exe  -I../src -I../ext/c4core/src -O3 -DNDEBUG -std=c++11 -MD -MT CMakeFiles/ryml.dir/src/c4/yml/tree.cpp.obj -MF CMakeFiles\ryml.dir\src\c4\yml\tree.cpp.obj.d -o CMakeFiles/ryml.dir/src/c4/yml/tree.cpp.obj -c ../src/c4/yml/tree.cpp
In file included from ../src/c4/yml/tree.cpp:1:
In file included from ../src\c4/yml/tree.hpp:10:
In file included from ../ext/c4core/src\c4/charconv.hpp:50:
In file included from ../ext/c4core/src\c4/ext/fast_float.hpp:14:
In file included from ../ext/c4core/src\c4/ext/./fast_float/include/fast_float/fast_float.h:44:
In file included from ../ext/c4core/src\c4/ext/./fast_float/include/fast_float/parse_number.h:3:
In file included from ../ext/c4core/src\c4/ext/./fast_float/include/fast_float/ascii_number.h:9:
../ext/c4core/src\c4/ext/./fast_float/include/fast_float/float_common.h:168:16: error: use of undeclared identifier '_umul128'
  answer.low = _umul128(a, b, &answer.high); // _umul128 not available on ARM64
               ^

_umul128() is declared in intrin.h, but it is not included in fast_float/float_common.h due to the following lines:

#if ((defined(_WIN32) || defined(_WIN64)) && !defined(__clang__))
#include <intrin.h>
#endif

So I think the condition should be changed, perhaps to #ifdef __MINGW32__?

[lemire]

clang+mingw on windows

I am not familiar with this particular platform. We support and test for gcc/mingw, and clangcl (clang on visual studio), but not clang/mingw at the moment.

Of course, before we support a platform, we should be able to test on it.

I think the condition should be changed, perhaps to #ifdef MINGW32?

If you are using clang, then I would expect __clang__ to be defined. And if you have clang, I would expect that you do not need <intrin.h>. You also should not be calling _umul128.

[lemire]

Can you tell me whether your system is 32 bits or 64 bits?

[lemire]

Issue reproduced at #46

[Gei0r]

The system and the compiler are both 64 bit.

If you are using clang, then I would expect __clang__ to be defined.

It is.

And if you have clang, I would expect that you do not need <intrin.h>.

Looks like it's required for _umul128().

You also should not be calling _umul128.

But it's done in full_multiplication() in float_common.h.

[lemire]

@Gei0r Yes. I understand that it is not working currently. My comments had to do with what ought to happen.

I will fix this issue soon. Your issue is valid and needs to be fixed.

[Gei0r]

Ah ok, sorry for mis-understanding.

[lemire]

Please update to v0.4.0. It should solve the issue. If not, please re-open another issue.

CI tests were added.

[Gei0r]

Works out, thank you!