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libstdc++: Reduce header dependencies for C++20 (PR 92546)

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In C++20 <memory> depends on <bits/ranges_unitialized.h> which
depends on <bits/random.h> just for a single concept. Including
<bits/random.h> also requires including <cmath>, which is huge due to
the C++17 special functions.

This change moves the concept to the <bits/uniform_int_dist.h> internal
header that exists so that <bits/stl_algobase.h> doesn't need to include
<bits/random.h>.

	PR libstdc++/92546 (partial)
	* include/bits/random.h (uniform_random_bit_generator): Move definition
	to <bits/uniform_int_dist.h>.
	* include/bits/ranges_algo.h: Include <bits/uniform_int_dist.h> instead
	of <bits/random.h>.
	* include/bits/ranges_algobase.h: Do not include <cmath>.
	* include/bits/uniform_int_dist.h (uniform_random_bit_generator):
	Move here.
	* include/std/ranges: Do not include <limits>.
	* testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error lineno.
This commit is contained in:
Jonathan Wakely 2020-02-17 15:25:33 +00:00
parent c03b53da91
commit 9cd4eeefcc
7 changed files with 30 additions and 19 deletions
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11
libstdc++-v3/ChangeLog
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@ -1,5 +1,16 @@
2020-02-17 Jonathan Wakely <jwakely@redhat.com>
PR libstdc++/92546 (partial)
* include/bits/random.h (uniform_random_bit_generator): Move definition
to <bits/uniform_int_dist.h>.
* include/bits/ranges_algo.h: Include <bits/uniform_int_dist.h> instead
of <bits/random.h>.
* include/bits/ranges_algobase.h: Do not include <cmath>.
* include/bits/uniform_int_dist.h (uniform_random_bit_generator):
Move here.
* include/std/ranges: Do not include <limits>.
* testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error lineno.
PR libstdc++/92546 (partial)
* include/Makefile.am: Add new header.
* include/Makefile.in: Regenerate.

16
libstdc++-v3/include/bits/random.h
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@ -33,9 +33,6 @@
#include <vector>
#include <bits/uniform_int_dist.h>
#if __cplusplus > 201703L
# include <concepts>
#endif
namespace std _GLIBCXX_VISIBILITY(default)
{
@ -51,18 +48,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
* @{
*/
#ifdef __cpp_lib_concepts
/// Requirements for a uniform random bit generator.
template<typename _Gen>
concept uniform_random_bit_generator
= invocable<_Gen&> && unsigned_integral<invoke_result_t<_Gen&>>
&& requires
{
{ _Gen::min() } -> same_as<invoke_result_t<_Gen&>>;
{ _Gen::max() } -> same_as<invoke_result_t<_Gen&>>;
requires bool_constant<(_Gen::min() < _Gen::max())>::value;
};
#endif
// std::uniform_random_bit_generator is defined in <bits/uniform_int_dist.h>
/**
* @brief A function template for converting the output of a (integral)

2
libstdc++-v3/include/bits/ranges_algo.h
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@ -33,7 +33,7 @@
#if __cplusplus > 201703L
#include <bits/ranges_algobase.h>
#include <bits/random.h> // concept uniform_random_bit_generator
#include <bits/uniform_int_dist.h> // concept uniform_random_bit_generator
#if __cpp_lib_concepts
namespace std _GLIBCXX_VISIBILITY(default)

1
libstdc++-v3/include/bits/ranges_algobase.h
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@ -32,7 +32,6 @@
#if __cplusplus > 201703L
#include <cmath>
#include <compare>
#include <iterator>
// #include <bits/range_concepts.h>

16
libstdc++-v3/include/bits/uniform_int_dist.h
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@ -33,11 +33,27 @@
#include <type_traits>
#include <limits>
#if __cplusplus > 201703L
# include <concepts>
#endif
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
#ifdef __cpp_lib_concepts
/// Requirements for a uniform random bit generator.
template<typename _Gen>
concept uniform_random_bit_generator
= invocable<_Gen&> && unsigned_integral<invoke_result_t<_Gen&>>
&& requires
{
{ _Gen::min() } -> same_as<invoke_result_t<_Gen&>>;
{ _Gen::max() } -> same_as<invoke_result_t<_Gen&>>;
requires bool_constant<(_Gen::min() < _Gen::max())>::value;
};
#endif
namespace __detail
{
/* Determine whether number is a power of 2. */

1
libstdc++-v3/include/std/ranges
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@ -42,7 +42,6 @@
#include <compare>
#include <initializer_list>
#include <iterator>
#include <limits>
#include <optional>
#include <tuple>

2
libstdc++-v3/testsuite/26_numerics/random/pr60037-neg.cc
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@ -10,6 +10,6 @@ std::__detail::_Adaptor<std::mt19937, unsigned long> aurng(urng);
auto x = std::generate_canonical<std::size_t,
std::numeric_limits<std::size_t>::digits>(urng);
// { dg-error "static assertion failed: template argument must be a floating point type" "" { target *-*-* } 172 }
// { dg-error "static assertion failed: template argument must be a floating point type" "" { target *-*-* } 158 }
// { dg-error "static assertion failed: template argument must be a floating point type" "" { target *-*-* } 3281 }