Avoid redundant get_loop_body calls in IVOPTs

Avoid redundant get_loop_body calls in IVOPTs

This removes redundant get_loop_body calls in IVOPTs by passing
around the body we're gathering early.

2021-11-23  Richard Biener  <rguenther@suse.de>

	* tree-ssa-loop-ivopts.c (find_givs): Take loop body as
	argument instead of re-computing it.
	(find_interesting_uses): Likewise.
	(find_induction_variables): Pass through loop body.
	(tree_ssa_iv_optimize_loop): Pass down loop body.