[PR68603] Associate conditional C++ loop's back-jump with start, not body

[PR68603] Associate conditional C++ loop's back-jump with start, not body

SVN commit r230979 always associates a loop's back-jump with the start
of the loop body.  This caused a regression for gcov with conditional
loops, because then the loop body appears to be covered twice per
iteration.

2015-12-02  Andreas Arnez  <arnez@linux.vnet.ibm.com>

	PR gcov-profile/68603
	* cp-gimplify.c (genericize_cp_loop): For the back-jump's location
	use the start of the loop body only if the loop is unconditional.

From-SVN: r231146