libstdc++-v3/testsuite/26_numerics/bit/bit.pow.two/ceil2.cc

   1 // Copyright (C) 2018-2019 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17
  18 // { dg-options "-std=gnu++2a" }
  19 // { dg-do compile { target c++2a } }
  20
  21 #include <bit>
  22
  23 template<typename UInt>
  24 constexpr auto
  25 test(UInt x)
  26 -> decltype(std::ceil2(x))
  27 {
  28   static_assert( noexcept(std::ceil2(x)) );
  29
  30   static_assert( std::ceil2(UInt(0)) == 1 );
  31   static_assert( std::ceil2(UInt(1)) == 1 );
  32   static_assert( std::ceil2(UInt(2)) == 2 );
  33   static_assert( std::ceil2(UInt(3)) == 4 );
  34   static_assert( std::ceil2(UInt(4)) == 4 );
  35   static_assert( std::ceil2(UInt(0x11)) == 0x20 );
  36   static_assert( std::ceil2(UInt(0x20)) == 0x20 );
  37
  38   if constexpr (std::numeric_limits<UInt>::digits > 8)
  39   {
  40     static_assert( std::ceil2(UInt(0x201)) == 0x400 );
  41     static_assert( std::ceil2(UInt(0x8ff)) == 0x1000 );
  42     static_assert( std::ceil2(UInt(0x1000)) == 0x1000 );
  43   }
  44
  45   if constexpr (std::numeric_limits<UInt>::digits > 32)
  46   {
  47     static_assert( std::ceil2(UInt(0xabcdef)) == 0x1000000 );
  48     static_assert( std::ceil2(UInt(0x1000000)) == 0x1000000 );
  49     static_assert( std::ceil2(UInt(0x1000001)) == 0x2000000 );
  50   }
  51
  52   if constexpr (std::numeric_limits<UInt>::digits > 64)
  53   {
  54     static_assert( std::ceil2(UInt(1) << 64) == (UInt(1) << 64) );
  55     static_assert( std::ceil2(UInt(3) << 64) == (UInt(4) << 64) );
  56   }
  57
  58   constexpr UInt msb = UInt(1) << (std::numeric_limits<UInt>::digits - 1);
  59   static_assert( std::ceil2( msb ) == msb );
  60   // Larger values cannot be represented so the return value is unspecified,
  61   // but must still be valid in constant expressions, i.e. not undefined.
  62   static_assert( std::ceil2( UInt(msb + 1) ) != 77 );
  63   static_assert( std::ceil2( UInt(msb + 2) ) != 77 );
  64   static_assert( std::ceil2( UInt(msb + 77) ) != 77 );
  65
  66   return true;
  67 }
  68
  69 static_assert( test( (unsigned char)0 ) );
  70 static_assert( test( (unsigned short)0 ) );
  71 static_assert( test( (unsigned int)0 ) );
  72 static_assert( test( (unsigned long)0 ) );
  73 static_assert( test( (unsigned long long)0 ) );
  74
  75 // std::ceil2(T) shall not participate in overload resolution
  76 // unless T is an unsigned integer type.
  77 struct X { constexpr bool did_not_match() { return true; } };
  78 constexpr X test(...) { return X{}; }
  79 static_assert( test( (bool)0 ).did_not_match() );
  80 static_assert( test( (char)0 ).did_not_match() );
  81 static_assert( test( (int)0 ).did_not_match() );
  82 static_assert( test( (char16_t)0 ).did_not_match() );
  83 static_assert( test( (float)0 ).did_not_match() );
  84 static_assert( test( (void*)0 ).did_not_match() );
  85 static_assert( test( X{} ).did_not_match() );
  86 enum E : unsigned { e };
  87 static_assert( test( e ).did_not_match() );
  88
  89 #if !defined(__STRICT_ANSI__) && defined _GLIBCXX_USE_INT128
  90 static_assert( test( (unsigned __int128)0 ) );
  91 static_assert( test( (__int128)0 ).did_not_match() );
  92 #endif
  93 #if defined(__GLIBCXX_TYPE_INT_N_0)
  94 static_assert( test( (unsigned __GLIBCXX_TYPE_INT_N_0)0 ) );
  95 static_assert( test( (__GLIBCXX_TYPE_INT_N_0)0 ).did_not_match() );
  96 #endif
  97 #if defined(__GLIBCXX_TYPE_INT_N_1)
  98 static_assert( test( (unsigned __GLIBCXX_TYPE_INT_N_1)0 ) );
  99 static_assert( test( (__GLIBCXX_TYPE_INT_N_1)0 ).did_not_match() );
 100 #endif
 101 #if defined(__GLIBCXX_TYPE_INT_N_2)
 102 static_assert( test( (unsigned __GLIBCXX_TYPE_INT_N_2)0 ) );
 103 static_assert( test( (__GLIBCXX_TYPE_INT_N_2)0 ).did_not_match() );
 104 #endif
 105 #if defined(__GLIBCXX_TYPE_INT_N_3)
 106 static_assert( test( (unsigned __GLIBCXX_TYPE_INT_N_3)0 ) );
 107 static_assert( test( (__GLIBCXX_TYPE_INT_N_3)0 ).did_not_match() );
 108 #endif
 109
 110 #include <cstddef>
 111 static_assert( test( (std::byte)0 ).did_not_match() );