tree-optimization/106226 - move vectorizer virtual SSA update

tree-optimization/106226 - move vectorizer virtual SSA update

When we knowingly have broken virtual SSA form we need to update
it before we eventually perform slpeel manual updating which will
call delete_update_ssa.  Currently that's done on-demand but
communicating whether it's a known unavoidable case is broken
there.  The following makes that a synchronous operation but
instead of actually performing the update we instead recod the
need, clear the update SSA sub-state and force virtual renaming
at the very end of the vectorization pass.

	PR tree-optimization/106226
	* tree-vect-loop-manip.cc (vect_do_peeling): Assert that
	no SSA update is needed.  Move virtual SSA update ...
	* tree-vectorizer.cc (pass_vectorize::execute): ... here,
	via forced virtual renaming when TODO_update_ssa_only_virtuals
	is queued.
	(vect_transform_loops): Return TODO_update_ssa_only_virtuals
	when virtual SSA update is required.
	(try_vectorize_loop_1): Adjust.
	* tree-vect-stmts.cc (vectorizable_simd_clone_call): Allow
	virtual renaming if the ABI forces an aggregate return
	but the original call did not have a virtual definition.

	* gfortran.dg/pr106226.f: New testcase.