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| author | Jonathan Wakely <jwakely@redhat.com> | 2020-02-17 14:30:02 +0000 |
|---|---|---|
| committer | Jonathan Wakely <jwakely@redhat.com> | 2020-02-17 15:11:04 +0000 |
| commit | c03b53da9129ae2d5ac9629c4b874d0981a7d418 (patch) | |
| tree | c93017e5e0b7094038b5b8d282aa3e243e557f07 /libstdc++-v3/include/bits/parse_numbers.h | |
| parent | 4540ef781bcefffe779a8b31950ea737733f06a4 (diff) | |
| download | gcc-c03b53da9129ae2d5ac9629c4b874d0981a7d418.tar.gz | |
libstdc++: Add lightweight replacement for std::numeric_limits (PR 92546)
Many uses of std::numeric_limits in C++17 and C++20 features only really
need the min(), max() and digits constants for integral types. By adding
__detail::__int_limits we can avoid including the whole <limits> header.
The <limits> header isn't especially large, but avoiding it still gives
small savings in compilation time and memory usage for the compiler.
There are also C++11 features that could benefit from this change (e.g.
<bits/hashtable_policy.h> and <bits/uniform_int_dist.h>) but I won't
change those until stage 1.
The implementation of __int_limits assumes two's complement integers,
which is true for all targets supported by GCC.
PR libstdc++/92546 (partial)
* include/Makefile.am: Add new header.
* include/Makefile.in: Regenerate.
* include/bits/int_limits.h: New header.
* include/bits/parse_numbers.h (__select_int::_Select_int): Replace
numeric_limits with __detail::__int_limits.
* include/std/bit (__rotl, __rotr, __countl_zero, __countl_one)
(__countr_zero, __countr_one, __popcount, __ceil2, __floor2, __log2p1):
Likewise.
* include/std/charconv (__to_chars_8, __from_chars_binary)
(__from_chars_alpha_to_num, from_chars): Likewise.
* include/std/memory_resource (polymorphic_allocator::allocate)
(polymorphic_allocator::allocate_object): Likewise.
* include/std/string_view (basic_string_view::_S_compare): Likewise.
* include/std/utility (in_range): Likewise.
* testsuite/20_util/integer_comparisons/in_range_neg.cc: Adjust for
extra error about incomplete type __int_limits<bool>.
* testsuite/26_numerics/bit/bit.count/countl_one.cc: Include <limits>.
* testsuite/26_numerics/bit/bit.count/countl_zero.cc: Likewise.
* testsuite/26_numerics/bit/bit.count/countr_one.cc: Likewise.
* testsuite/26_numerics/bit/bit.count/countr_zero.cc: Likewise.
* testsuite/26_numerics/bit/bit.count/popcount.cc: Likewise.
* testsuite/26_numerics/bit/bit.pow.two/ceil2_neg.cc: Likewise.
* testsuite/26_numerics/bit/bit.pow.two/ceil2.cc: Likewise.
* testsuite/26_numerics/bit/bit.pow.two/floor2.cc: Likewise.
* testsuite/26_numerics/bit/bit.pow.two/ispow2.cc: Likewise.
* testsuite/26_numerics/bit/bit.pow.two/log2p1.cc: Likewise.
* testsuite/26_numerics/bit/bit.rotate/rotl.cc: Likewise.
* testsuite/26_numerics/bit/bit.rotate/rotr.cc: Likewise.
Diffstat (limited to 'libstdc++-v3/include/bits/parse_numbers.h')
| -rw-r--r-- | libstdc++-v3/include/bits/parse_numbers.h | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/libstdc++-v3/include/bits/parse_numbers.h b/libstdc++-v3/include/bits/parse_numbers.h index d7a81e55182..6a75d002774 100644 --- a/libstdc++-v3/include/bits/parse_numbers.h +++ b/libstdc++-v3/include/bits/parse_numbers.h @@ -34,9 +34,9 @@ // From n3642.pdf except I added binary literals and digit separator '\''. -#if __cplusplus > 201103L +#if __cplusplus >= 201402L -#include <limits> +#include <bits/int_limits.h> namespace std _GLIBCXX_VISIBILITY(default) { @@ -265,7 +265,7 @@ namespace __select_int template<unsigned long long _Val, typename _IntType, typename... _Ints> struct _Select_int_base<_Val, _IntType, _Ints...> - : conditional_t<(_Val <= std::numeric_limits<_IntType>::max()), + : conditional_t<(_Val <= __detail::__int_limits<_IntType>::max()), integral_constant<_IntType, _Val>, _Select_int_base<_Val, _Ints...>> { }; @@ -289,6 +289,6 @@ namespace __select_int _GLIBCXX_END_NAMESPACE_VERSION } // namespace std -#endif // __cplusplus > 201103L +#endif // C++14 #endif // _GLIBCXX_PARSE_NUMBERS_H |