diff options
Diffstat (limited to 'current/sources/cxx-stl/llvm-libc++abi/test/dynamic_cast_stress.pass.cpp')
-rw-r--r-- | current/sources/cxx-stl/llvm-libc++abi/test/dynamic_cast_stress.pass.cpp | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/current/sources/cxx-stl/llvm-libc++abi/test/dynamic_cast_stress.pass.cpp b/current/sources/cxx-stl/llvm-libc++abi/test/dynamic_cast_stress.pass.cpp new file mode 100644 index 000000000..73b398f47 --- /dev/null +++ b/current/sources/cxx-stl/llvm-libc++abi/test/dynamic_cast_stress.pass.cpp @@ -0,0 +1,80 @@ +//===------------------------- dynamic_cast_stress.cpp --------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +// UNSUPPORTED: c++98, c++03 + +#include <cassert> +#include <tuple> +#include "support/timer.h" + +template <std::size_t Indx, std::size_t Depth> +struct C + : public virtual C<Indx, Depth-1>, + public virtual C<Indx+1, Depth-1> +{ + virtual ~C() {} +}; + +template <std::size_t Indx> +struct C<Indx, 0> +{ + virtual ~C() {} +}; + +template <std::size_t Indx, std::size_t Depth> +struct B + : public virtual C<Indx, Depth-1>, + public virtual C<Indx+1, Depth-1> +{ +}; + +template <class Indx, std::size_t Depth> +struct makeB; + +template <std::size_t ...Indx, std::size_t Depth> +struct makeB<std::__tuple_indices<Indx...>, Depth> + : public B<Indx, Depth>... +{ +}; + +template <std::size_t Width, std::size_t Depth> +struct A + : public makeB<typename std::__make_tuple_indices<Width>::type, Depth> +{ +}; + +void test() +{ + const std::size_t Width = 10; + const std::size_t Depth = 5; + A<Width, Depth> a; + typedef B<Width/2, Depth> Destination; +// typedef A<Width, Depth> Destination; + Destination *b = nullptr; + { + timer t; + b = dynamic_cast<Destination*>((C<Width/2, 0>*)&a); + } + assert(b != 0); +} + +int main() +{ + test(); +} + +/* +Timing results I'm seeing (median of 3 microseconds): + + libc++abi gcc's dynamic_cast +B<Width/2, Depth> -O3 48.334 93.190 libc++abi 93% faster +B<Width/2, Depth> -Os 58.535 94.103 libc++abi 61% faster +A<Width, Depth> -O3 11.515 33.134 libc++abi 188% faster +A<Width, Depth> -Os 12.631 31.553 libc++abi 150% faster + +*/ |