http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47913
--- Comment #17 from Marc Glisse <marc.glisse at normalesup dot org> 2011-03-02 20:50:42 UTC --- Some more examples. Using the constants: m=INTMAX_MAX; n=INTMAX_MAX/2; p=((intmax_t)1<<(4*sizeof(intmax_t)-1))-3 (m,2)-(m,3)==(m,6) boost should manage this one (m/7*5-1,5)-(m-2,7) __big_mul would be enough (__big_div is the hard thing) (n-5,15)+(n,35) one could cheat by removing the integral part (p^2,(2*p-3)*(p-2))-(p+2,(p-1)*(p-2)) one may be able to write gcd=(p-2), p^2 as (p+2)*gcd+4 and the computation of the numerator becomes gcd*((p+2)*(p-1)-(2*p-3))+4*(p-1)-4*(2*p-3) and both computations (p+2)*(p-1)-(2*p-3) and 4*(p-1)-4*(2*p-3) fit in a intmax_t. But with a larger gcd, they may not (I'll try to add an example later).
