Hi,

Attached is the patch to fix bug 44503: "control flow in the middle of basic block" with -fprefetch-loop-arrays.

The problem is that a non-local label (for setjmp) exists in the function. When we insert a _builtin_prefetch
call, this prefetch is considered potentially changing the control flow. We think this is, in general, a loop 
construction problem. When the current function has non local labels, there are no natural loops in the 
function. 

The patch passed bootstrapping and gcc regression tests on amd-linux64 systems.

Is it ok for the trunk?

Thanks,

Changpeng