When versioning is run the IL is already mangled and finding
a VECTORIZED_CALL IFN can fail.

2020-01-20  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/93094
	* tree-vectorizer.h (vect_loop_versioning): Adjust.
	(vect_transform_loop): Likewise.
	* tree-vectorizer.c (try_vectorize_loop_1): Pass down
	loop_vectorized_call to vect_transform_loop.
	* tree-vect-loop.c (vect_transform_loop): Pass down
	loop_vectorized_call to vect_loop_versioning.
	* tree-vect-loop-manip.c (vect_loop_versioning): Use
	the earlier discovered loop_vectorized_call.

	* gcc.dg/vect/pr93094.c: New testcase.