middle-end: don't set range on partial vectors [PR120922]

Before the change in g:309dbcea2cabb31bde1a65cdfd30bb7f87b170a2 we would never
set a range for constant VF and requires partial vector loops.

I think a range could be set, since I think the number of latch executions is a
ceiling division of TYPE_MAX_VALUE / vf. To account for the partial iteration.

This would also then deal with the ICE cause in the PR where the chosen VF was
much higher than TYPE_MAX_VALUE and that a mask is relied upon to make it safe.

Since the patch was supposed to not change behavior I've added an additional
partial vector check on the const_vf > 0 check to make it explicit that we only
set it on non-partial vectors (alternative would have been to swap the order of
the vf.constant(&const_vf)) check, but that would have hidden the requirement
sneakily.

The second patch adds support for ranges for partial masks.

gcc/ChangeLog:

	PR tree-optimization/120922
	* tree-vect-loop-manip.cc (vect_gen_vector_loop_niters): Don't set range
	for partial vectors.

gcc/testsuite/ChangeLog:

	PR tree-optimization/120922
	* gcc.dg/vect/pr120922.c: New test.

0 files changed, 0 insertions, 0 deletions