This fixes the following:

Excess errors:

gcc/testsuite/gcc.c-torture/compile/pr55569.c:13:12: warning: overflow 
in conversion from 'long long unsigned int' to 'long int' changes value 
from '4611686018427387903' to '-1' [-Woverflow]

gcc/testsuite/gcc.c-torture/compile/pr55569.c:13:34: warning: iteration 
2147483647 invokes undefined behavior [-Waggressive-loop-optimizations]

Patch OK?