33 lines
736 B
C++
33 lines
736 B
C++
/* SPDX-FileCopyrightText: 2024 Blender Authors
|
|
*
|
|
* SPDX-License-Identifier: GPL-2.0-or-later */
|
|
|
|
/** \file
|
|
* \ingroup bli
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include <cstdlib>
|
|
#include <utility>
|
|
|
|
namespace blender {
|
|
|
|
template<class Fn, size_t... I>
|
|
constexpr void unroll_impl(Fn fn, std::index_sequence<I...> /*indices*/)
|
|
{
|
|
(fn(I), ...);
|
|
}
|
|
|
|
/**
|
|
* Variadic templates are used to unroll loops manually. This helps GCC avoid branching during math
|
|
* operations and makes the code generation more explicit and predictable. Unrolling should always
|
|
* be worth it because the vector size is expected to be small.
|
|
*/
|
|
template<int N, class Fn> constexpr void unroll(Fn fn)
|
|
{
|
|
unroll_impl(fn, std::make_index_sequence<N>());
|
|
}
|
|
|
|
} // namespace blender
|