middle-end: don't cache restart_loop in vectorizable_live_operations [PR113808]

middle-end: don't cache restart_loop in vectorizable_live_operations [PR113808]

There's a bug in vectorizable_live_operation that restart_loop is defined
outside the loop.

This variable is supposed to indicate whether we are doing a first or last
index reduction.  The problem is that by defining it outside the loop it becomes
dependent on the order we visit the USE/DEFs.

In the given example, the loop isn't PEELED, but we visit the early exit uses
first.  This then sets the boolean to true and it can't get to false again.

So when we visit the main exit we still treat it as an early exit for that
SSA name.

This cleans it up and renames the variables to something that's hopefully
clearer to their intention.

gcc/ChangeLog:

	PR tree-optimization/113808
	* tree-vect-loop.cc (vectorizable_live_operation): Don't cache the
	value cross iterations.

gcc/testsuite/ChangeLog:

	PR tree-optimization/113808
	* gfortran.dg/vect/vect-early-break_1-PR113808.f90: New test.