Ambiguous fma/fnma calls

[Martmists-GH]

Seems to only happen on exp and log, error:

/home/mart/git/kotlin/kt-ndarray-simd/xsimd/include/xsimd/types/xsimd_api.hpp:958:16: error: call to 'fnma' is ambiguous
        return kernel::fnma<A>(x, y, z, A {});
               ^~~~~~~~~~~~~~~
/home/mart/git/kotlin/kt-ndarray-simd/xsimd/include/xsimd/arch/./generic/xsimd_generic_math.hpp:816:26: note: in instantiation of function template specialization 'xsimd::fnma<double, xsimd::fma4>' requested here
                    hi = fnma(k, constants::log_2hi<batch_type>(), a);
                         ^
/home/mart/git/kotlin/kt-ndarray-simd/xsimd/include/xsimd/arch/./generic/xsimd_generic_math.hpp:903:43: note: in instantiation of member function 'xsimd::kernel::detail::exp_reduction<double, xsimd::fma4, xsimd::kernel::detail::exp_tag>::reduce' requested here
                batch_type k = reducer_t::reduce(self, hi, lo, x);
                                          ^
/home/mart/git/kotlin/kt-ndarray-simd/xsimd/include/xsimd/arch/./generic/xsimd_generic_math.hpp:915:28: note: in instantiation of function template specialization 'xsimd::kernel::detail::exp<xsimd::kernel::detail::exp_tag, xsimd::fma4>' requested here
            return detail::exp<detail::exp_tag>(self);
                           ^
/home/mart/git/kotlin/kt-ndarray-simd/xsimd/include/xsimd/types/xsimd_api.hpp:720:24: note: in instantiation of function template specialization 'xsimd::kernel::exp<xsimd::fma4, double>' requested here
        return kernel::exp<A>(x, A {});
                       ^
/home/mart/git/kotlin/kt-ndarray-simd/src/lib/arch/../cpp/math_priv.h:96:27: note: in instantiation of function template specialization 'xsimd::exp<double, xsimd::fma4>' requested here
        auto res = xsimd::exp(va);
                          ^
/home/mart/git/kotlin/kt-ndarray-simd/xsimd/include/xsimd/arch/./xsimd_fma4.hpp:32:39: note: candidate function [with A = xsimd::fma4]
        XSIMD_INLINE batch<double, A> fnma(simd_register<double, A> const& x, simd_register<double, A> const& y, simd_register<double, A> const& z, requires_arch<fma4>) noexcept
                                      ^
/home/mart/git/kotlin/kt-ndarray-simd/xsimd/include/xsimd/arch/./generic/xsimd_generic_arithmetic.hpp:102:34: note: candidate function [with A = xsimd::fma4, T = double]
        XSIMD_INLINE batch<T, A> fnma(batch<T, A> const& x, batch<T, A> const& y, batch<T, A> const& z, requires_arch<generic>) noexcept
                                 ^

Code:

struct _vec_exp { template <class Arch> void operator()(Arch, double* a, int n); };
static auto _vec_exp_dispatcher = xsimd::dispatch<arch_list>(_vec_exp{});
// extern for each arch here
template <class Arch> void _vec_exp::operator()(Arch, double* a, int n) {
    using batch = xsimd::batch<double, Arch>;

    std::size_t size = n - n % batch::size;

    for (std::size_t i = 0; i < size; i += batch::size) {
        auto va = batch::load_unaligned(&a[i]);
        auto res = xsimd::exp(va);
        xsimd::store_unaligned(&a[i], res);
    }

    for (std::size_t i = size; i < n; ++i) {
        a[i] = std::exp(a[i]);
    }
}

xsimd version 13.0.0

[Martmists-GH]

Seems to happen when compiling for fma4, fma3+sse4.2 works fine.

generated clang invocation:

/home/mart/.konan/dependencies/llvm-16.0.0-x86_64-linux-essentials-80/bin/clang 
  -B/home/mart/.konan/dependencies/x86_64-unknown-linux-gnu-gcc-8.3.0-glibc-2.19-kernel-4.9-2/x86_64-unknown-linux-gnu/bin 
  -fno-stack-protector
  --gcc-toolchain=/home/mart/.konan/dependencies/x86_64-unknown-linux-gnu-gcc-8.3.0-glibc-2.19-kernel-4.9-2
  -target x86_64-unknown-linux-gnu
  --sysroot=/home/mart/.konan/dependencies/x86_64-unknown-linux-gnu-gcc-8.3.0-glibc-2.19-kernel-4.9-2/x86_64-unknown-linux-gnu/sysroot
  -fPIC 
  /home/mart/git/kotlin/kt-ndarray-simd/src/lib/arch/fma4.cpp
  -c
  -o /home/mart/git/kotlin/kt-ndarray-simd/build/cinterop/linuxX64/fma4.o
  -O2 
  -mfma4 -msse4.2 -msse4.1 -mssse3 -msse3 -msse2
  -I/home/mart/git/kotlin/kt-ndarray-simd/src/lib/public 
  -I/home/mart/git/kotlin/kt-ndarray-simd/xsimd/include

[Martmists-GH]

Reproducer: https://godbolt.org/z/dsYx3rWPr

[serge-sans-paille]

Can you confirm #1072 fixes your issue?

[Martmists-GH]

That does seem to fix it :)