[Bug c++/58430] New: GCC hangs with 100% cpu core utilization during template compilation

[Bug c++/58430] New: GCC hangs with 100% cpu core utilization during template compilation

[apirogov@manage-it.ru]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58430

            Bug ID: 58430
           Summary: GCC hangs with 100% cpu core utilization during
                    template compilation
           Product: gcc
           Version: 4.7.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: apirogov@manage-it.ru

The next code leads hanging up of the compiler:

template<unsigned I1, unsigned I2>
void test()
{
    test<I1 + ((I2 - I1) / 2) + 1, I2>();
    test<I1, I1 + ((I2 - I1) / 2) >();
};

int main() 
{
    test<0, 0>();
    return 0;
}

[Bug c++/58430] GCC hangs with 100% cpu core utilization during template compilation

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58430

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |INVALID

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
You are instantitating 2^900 templates which will take quite some time.
Lower -ftemplate-depth to something reasonable (the default is 900) to
get an error:

> g++-4.7 -S t.C -ftemplate-depth=3
t.C:4:3: error: template instantiation depth exceeds maximum of 3 (use
-ftemplate-depth= to increase the maximum) substituting 'template<unsigned int
I1, unsigned int I2> void test() [with unsigned int I1 = 3221225473u; unsigned
int I2 = 0u]'
t.C:4:3:   recursively required from 'void test() [with unsigned int I1 = 1u;
unsigned int I2 = 0u]'
t.C:4:3:   required from 'void test() [with unsigned int I1 = 0u; unsigned int
I2 = 0u]'
t.C:10:14:   required from here

Or limit instantiation by providing a terminating specialization.