https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70340
Bug ID: 70340
Summary: Invalid constexpr template function causes internal
compiler error (memory exhaustion)
Product: gcc
Version: 5.3.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: gccBugs at haatschii dot de
Target Milestone: ---
Working with GMP I came across an error which causes the GCC to use an
exhaustive amount of memory (> 32 GB). The problem boils down to the following
example:
#include <gmpxx.h>
template<class T>
constexpr T pow(const T& _base, const uint64_t _exp) {
return _exp==0 ? 1 :(_exp%2==0?pow(_base*_base, _exp/2) :
_base*pow(_base, _exp-1));
}
int main ( const int argC, char* argV[] ) {
mpz_class test = pow( mpz_class(10), 73ul);
return 0;
}
Note that this code is invalid because different types are used on the
different sides of the ":" in both ternary operators. This is correctly pointed
out by the g++ if the "constexpr" is removed. However with the "constexpr" it
crashes.
My version is:
g++ (GCC) 5.3.1 20151207 (Red Hat 5.3.1-2)
Best regards,
Sebastian
