Don't reduce estimated unrolled size for innermost loop.

Don't reduce estimated unrolled size for innermost loop.

For the innermost loop, after completely loop unroll, it will most likely
not be able to reduce the body size to 2/3. The current 2/3 reduction
will make some of the larger loops completely unrolled during
cunrolli, which will then result in them not being able to be
vectorized. It also increases the register pressure.

The patch move the 2/3 reduction from estimated_unrolled_size to
tree_unroll_loops_completely.

gcc/ChangeLog:

	PR tree-optimization/112325
	* tree-ssa-loop-ivcanon.cc (estimated_unrolled_size): Move the
	2 / 3 loop body size reduction to ..
	(try_unroll_loop_completely): .. here, add it for the check of
	body size shrink, and the check of comparison against
	param_max_completely_peeled_insns when
	(!cunrolli ||loop->inner).
	(canonicalize_loop_induction_variables): Add new parameter
	cunrolli and pass down.
	(tree_unroll_loops_completely_1): Ditto.
	(canonicalize_induction_variables): Pass cunrolli as false to
	canonicalize_loop_induction_variables.
	(tree_unroll_loops_completely): Set cunrolli to true at
	beginning and set it to false after CHANGED is true.

gcc/testsuite/ChangeLog:

	* gcc.dg/vect/pr112325.c: New test.