In do_warn_aggressive_loop_optimizations, we convert to a tree just to print a
widest_int. Apart from overly complicated, this results in printing '3u'
instead of just '3'.

Unfortunately, adding a printf-like conversion specifier would require making
pretty-print.c link with wide-int.cc, which will include a lot of new
dependencies into several other programs (gcov-tool for example). It would be
possible to add the conversion specifier to every FE pretty-printer, but this
still would require updating c-format.c, which is far from trivial. A simpler
approach is to convert to a string rather than to a tree.

In addition, "iteration 3 invokes undefined behavior within this loop" seems to
me clearer than "iteration 3 invokes undefined behavior; containing loop".

gcc/testsuite/ChangeLog:

2015-09-21  Manuel López-Ibáñez  <manu@gcc.gnu.org>

	PR middle-end/60832
	* gcc.dg/pr53265.c: Update.

gcc/ChangeLog:

2015-09-21  Manuel López-Ibáñez  <manu@gcc.gnu.org>

	PR middle-end/60832
	* tree-ssa-loop-niter.c (do_warn_aggressive_loop_optimizations):
	Print i_bound without converting it to a tree.

From-SVN: r227964