clang/test/SemaCXX/builtins-overflow.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -std=c++17 -verify %s
   2 // expected-no-diagnostics
   3
   4 #include <limits.h>
   5 #include <stdint.h>
   6
   7 int a() {
   8   const int x = 3;
   9   static int z;
  10   constexpr int *y = &z;
  11   return []() { return __builtin_sub_overflow((int)x, (int)x, (int *)y); }();
  12 }
  13 int a2() {
  14   const int x = 3;
  15   static int z;
  16   constexpr int *y = &z;
  17   return []() { return __builtin_sub_overflow(x, x, y); }();
  18 }
  19
  20 template<typename T>
  21 struct Result {
  22   bool B;
  23   T Value;
  24   constexpr bool operator==(const Result<T> &Other) {
  25     return B == Other.B && Value == Other.Value;
  26   }
  27 };
  28
  29
  30 template <typename RET, typename LHS, typename RHS>
  31 constexpr Result<RET> add(LHS &&lhs, RHS &&rhs) {
  32   RET sum{};
  33   return {__builtin_add_overflow(lhs, rhs, &sum), sum};
  34 }
  35
  36 static_assert(add<short>(static_cast<char>(120), static_cast<char>(10)) == Result<short>{false, 130});
  37 static_assert(add<char>(static_cast<short>(120), static_cast<short>(10)) == Result<char>{true, -126});
  38 static_assert(add<unsigned int>(INT_MAX, INT_MAX) == Result<unsigned int>{false, static_cast<unsigned int>(INT_MAX) * 2u});
  39 static_assert(add<int>(static_cast<unsigned int>(INT_MAX), 1u) == Result<int>{true, INT_MIN});
  40
  41 static_assert(add<int>(17, 22) == Result<int>{false, 39});
  42 static_assert(add<int>(INT_MAX - 22, 24) == Result<int>{true, INT_MIN + 1});
  43 static_assert(add<int>(INT_MIN + 22, -23) == Result<int>{true, INT_MAX});
  44
  45 template <typename RET, typename LHS, typename RHS>
  46 constexpr Result<RET> sub(LHS &&lhs, RHS &&rhs) {
  47   RET sum{};
  48   return {__builtin_sub_overflow(lhs, rhs, &sum), sum};
  49 }
  50
  51 static_assert(sub<unsigned char>(static_cast<char>(0),static_cast<char>(1)) == Result<unsigned char>{true, UCHAR_MAX});
  52 static_assert(sub<char>(static_cast<unsigned char>(0),static_cast<unsigned char>(1)) == Result<char>{false, -1});
  53 static_assert(sub<unsigned short>(static_cast<short>(0),static_cast<short>(1)) == Result<unsigned short>{true, USHRT_MAX});
  54 static_assert(sub<uint8_t>(static_cast<uint8_t>(255),static_cast<int>(100)) == Result<uint8_t>{false, 155});
  55
  56 static_assert(sub<int>(17,22) == Result<int>{false, -5});
  57 static_assert(sub<int>(INT_MAX - 22, -23) == Result<int>{true, INT_MIN});
  58 static_assert(sub<int>(INT_MIN + 22, 23) == Result<int>{true, INT_MAX});
  59
  60 template <typename RET, typename LHS, typename RHS>
  61 constexpr Result<RET> mul(LHS &&lhs, RHS &&rhs) {
  62   RET sum{};
  63   return {__builtin_mul_overflow(lhs, rhs, &sum), sum};
  64 }
  65
  66 static_assert(mul<int>(17,22) == Result<int>{false, 374});
  67 static_assert(mul<int>(INT_MAX / 22, 23) == Result<int>{true, -2049870757});
  68 static_assert(mul<int>(INT_MIN / 22, -23) == Result<int>{true, -2049870757});
  69
  70 constexpr Result<int> sadd(int lhs, int rhs) {
  71   int sum{};
  72   return {__builtin_sadd_overflow(lhs, rhs, &sum), sum};
  73 }
  74
  75 static_assert(sadd(17,22) == Result<int>{false, 39});
  76 static_assert(sadd(INT_MAX - 22, 23) == Result<int>{true, INT_MIN});
  77 static_assert(sadd(INT_MIN + 22, -23) == Result<int>{true, INT_MAX});
  78
  79 constexpr Result<int> ssub(int lhs, int rhs) {
  80   int sum{};
  81   return {__builtin_ssub_overflow(lhs, rhs, &sum), sum};
  82 }
  83
  84 static_assert(ssub(17,22) == Result<int>{false, -5});
  85 static_assert(ssub(INT_MAX - 22, -23) == Result<int>{true, INT_MIN});
  86 static_assert(ssub(INT_MIN + 22, 23) == Result<int>{true, INT_MAX});
  87
  88 constexpr Result<int> smul(int lhs, int rhs) {
  89   int sum{};
  90   return {__builtin_smul_overflow(lhs, rhs, &sum), sum};
  91 }
  92
  93 static_assert(smul(17,22) == Result<int>{false, 374});
  94 static_assert(smul(INT_MAX / 22, 23) == Result<int>{true, -2049870757});
  95 static_assert(smul(INT_MIN / 22, -23) == Result<int>{true, -2049870757});
  96