[Bug c++/51433] New: constexpr caching leads to incorrect dynamic initialization

[richard-gccbugzilla at metafoo dot co.uk]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51433

             Bug #: 51433
           Summary: constexpr caching leads to incorrect dynamic
                    initialization
    Classification: Unclassified
           Product: gcc
           Version: 4.6.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: richard-gccbugzilla@metafoo.co.uk


Testcase:

constexpr int f();
constexpr int g() { return f(); }
extern const int n = g();
constexpr int f() { return 42; }
extern const int m = g();

g++ uses dynamic initialization for both m and n. Static initialization is
required to be used for m. We can upgrade this to a rejects-valid:

int arr[m]; // error!