31cbe0f240
C++98 and C++03 are effectively aliases as far as Clang is concerned. As such, allowing both std=c++98 and std=c++03 as Lit parameters is just slightly confusing, but provides no value. It's similar to allowing both std=c++17 and std=c++1z, which we don't do. This was discovered because we had an internal bot that ran the test suite under both c++98 AND c++03 -- one of which is redundant. Differential Revision: https://reviews.llvm.org/D80926
81 lines
1.9 KiB
C++
81 lines
1.9 KiB
C++
//===------------------------- dynamic_cast_stress.cpp --------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// UNSUPPORTED: c++03
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#include <cassert>
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#include <tuple>
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#include "support/timer.h"
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template <std::size_t Indx, std::size_t Depth>
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struct C
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: public virtual C<Indx, Depth-1>,
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public virtual C<Indx+1, Depth-1>
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{
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virtual ~C() {}
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};
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template <std::size_t Indx>
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struct C<Indx, 0>
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{
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virtual ~C() {}
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};
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template <std::size_t Indx, std::size_t Depth>
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struct B
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: public virtual C<Indx, Depth-1>,
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public virtual C<Indx+1, Depth-1>
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{
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};
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template <class Indx, std::size_t Depth>
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struct makeB;
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template <std::size_t ...Indx, std::size_t Depth>
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struct makeB<std::__tuple_indices<Indx...>, Depth>
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: public B<Indx, Depth>...
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{
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};
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template <std::size_t Width, std::size_t Depth>
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struct A
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: public makeB<typename std::__make_tuple_indices<Width>::type, Depth>
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{
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};
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void test()
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{
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const std::size_t Width = 10;
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const std::size_t Depth = 5;
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A<Width, Depth> a;
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typedef B<Width/2, Depth> Destination;
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// typedef A<Width, Depth> Destination;
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Destination *b = nullptr;
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{
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timer t;
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b = dynamic_cast<Destination*>((C<Width/2, 0>*)&a);
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}
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assert(b != 0);
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}
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int main()
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{
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test();
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}
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/*
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Timing results I'm seeing (median of 3 microseconds):
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libc++abi gcc's dynamic_cast
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B<Width/2, Depth> -O3 48.334 93.190 libc++abi 93% faster
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B<Width/2, Depth> -Os 58.535 94.103 libc++abi 61% faster
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A<Width, Depth> -O3 11.515 33.134 libc++abi 188% faster
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A<Width, Depth> -Os 12.631 31.553 libc++abi 150% faster
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*/
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