<cmath>: New intrinsics broke CUDA

[StephanTLavavej]

When #1336 added usage of new intrinsics to <cmath>, we forgot about CUDA. 🙀 (Long ago, we broke CUDA by adding new type traits intrinsics in C++14 mode, but these math functions were just different enough that I didn't remember the interaction. Oops!)

I'm not exactly sure why our CUDA unit test didn't catch this, given that the affected overloads aren't templates:

STL/stl/inc/cmath

Lines 62 to 70 in f675d68

	_NODISCARD _Check_return_ inline float ceil(_In_ float _Xx) noexcept /* strengthened */ {
	#ifdef _M_CEE
	return _CSTD ceilf(_Xx);
	#elif defined(__clang__)
	return __builtin_ceilf(_Xx);
	#else // ^^^ __clang__ / !__clang__ vvv
	return __ceilf(_Xx);
	#endif // __clang__
	}

We are including <cmath>, so there's probably some detail of the CUDA compilation process that I don't understand:

STL/stl/inc/__msvc_all_public_headers.hpp

Line 156 in f675d68

#include <cmath>

STL/tests/std/tests/GH_000639_nvcc_include_all/test.compile.pass.cpp

Lines 4 to 6 in f675d68

	#define _MSVC_TESTING_NVCC
	#include <__msvc_all_public_headers.hpp>

In any event, fixing this should be easy, we just need to backport it to VS 2019 16.9.

Originally encountered in pytorch/pytorch#54382 and tracked by Microsoft-internal VSO-1314894 / AB#1314894 .

[sylveon]

I believe the CI did not catch this because it only seems to happen when building device code, not host code (not familiar with CUDA but the error message seems to imply this)

[EricAtORS]

Is this related as well?
https://devtalk.blender.org/t/cuda-compile-error-windows-10/17886

I experienced that issue with other cuda as well, but the suggestion to switch from floor to floorf made it compile.

[sylveon]

Yes, floorf is unaffected because it comes from the UCRT, which the PR couldn't update since it isn't open source.

[IngmarVoigt2]

Hi @StephanTLavavej,

is this already on the latest Visual Studio releases? You mentioned this should be backported to v16.9, no? If not do you know when we could expect this to be released? I neither saw this on the release notes for v16.9 nor for v16.10.

Thx a lot!

[IngmarVoigt2]

Nevermind, I realized it's already in 16.10.2 at least

[StephanTLavavej]

@IngmarVoigt2 Yep, this shipped in 16.10.0 and was backported to 16.9.7. The VS and MSVC release notes don't contain this level of detail, but the STL's Changelog does - see https://github.com/microsoft/STL/wiki/Changelog#vs-2019-1610 and search for the PR number #1886.