https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64333
Bug ID: 64333
Summary: C++14 constexpr gives wrong results when a looping
constexpr function is evaluated twice
Product: gcc
Version: 5.0
Status: UNCONFIRMED
Keywords: wrong-code
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: ville.voutilainen at gmail dot com
CC: jason at redhat dot com
#include <initializer_list>
constexpr int max(std::initializer_list<int> ints)
{
int ret = *(ints.begin());
for (int i = 0; i < ints.size(); ++i) {
if (*(ints.begin()+i) > ret) {
ret = *(ints.begin()+i);
}
}
return ret;
}
int main()
{
constexpr int z = max({7,6,5,4,3,2,1});
constexpr int z2 = max({5,4,3,2,1});
static_assert(z == 7, "");
static_assert(z2 == 5, "");
}
z2 is 7. There's something fishy going on here. :)
