[Bug tree-optimization/59660] We fail to optimize common boolean checks pre-inlining

[hubicka at ucw dot cz]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59660

--- Comment #4 from Jan Hubicka <hubicka at ucw dot cz> ---
> Not all testcases can be handled at gimplification time IIRC.  Which
> means "testcases welcome" first, so we can look at them individually.

The GCC one I saw was equivalent of:
#include <stdbool.h>
bool
m_is_less_than_n (int n, int m)
{
   return (n==m || m_is_less_than_n (n-1,m));
}