re PR tree-optimization/81661 (ICE in gimplify_modify_expr, at gimplify.c:5638)

re PR tree-optimization/81661 (ICE in gimplify_modify_expr, at gimplify.c:5638)

	PR tree-optimization/81661
	PR tree-optimization/84117
	* tree-eh.h (rewrite_to_non_trapping_overflow): Declare.
	* tree-eh.c: Include gimplify.h.
	(find_trapping_overflow, replace_trapping_overflow,
	rewrite_to_non_trapping_overflow): New functions.
	* tree-vect-loop.c: Include tree-eh.h.
	(vect_get_loop_niters): Use rewrite_to_non_trapping_overflow.
	* tree-data-ref.c: Include tree-eh.h.
	(get_segment_min_max): Use rewrite_to_non_trapping_overflow.

	* gcc.dg/pr81661.c: New test.
	* gfortran.dg/pr84117.f90: New test.

From-SVN: r257284