Add a gimple_move_vops helper function

Add a gimple_move_vops helper function

I needed to add another instance of this idiom, so thought it'd
be worth having a helper function.

2019-08-05  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* gimple.h (gimple_move_vops): Declare.
	* gimple.c (gimple_move_vops): New function
	* gimple-fold.c (replace_call_with_call_and_fold)
	(gimple_fold_builtin_memory_op, gimple_fold_builtin_memset)
	(gimple_fold_builtin_stpcpy, fold_builtin_atomic_compare_exchange)
	(gimple_fold_call): Use it.
	* ipa-param-manipulation.c (ipa_modify_call_arguments): Likewise.
	* tree-call-cdce.c (use_internal_fn): Likewise.
	* tree-if-conv.c (predicate_load_or_store): Likewise.
	* tree-ssa-ccp.c (optimize_atomic_bit_test_and): Likewise.
	* tree-ssa-math-opts.c (pass_cse_reciprocals::execute): Likewise.
	* tree-ssa-propagate.c (finish_update_gimple_call): Likewise.
	(update_call_from_tree): Likewise.
	* tree-vect-stmts.c (vectorizable_load): Likewise.
	* tree-vectorizer.c (adjust_simduid_builtins): Likewise.

From-SVN: r274117