ipa-cp: Write transformation summaries of all functions

ipa-cp: Write transformation summaries of all functions

IPA-CP transformation summary streaming code currently won't stream
out transformations necessary for clones which are only necessary for
materialization of other clones (such as an IPA-CP clone which is then
cloned again by IPA-SRA).  However, a follow-up patch for bettor
reconciling IPA-SRA and IPA-CP modifications requires to have that
information at its disposal and so this one reworks the streaming to
write out all non-empty transformation summaries.

In order not to stream transformation summaies into partitions where
the node itself nor any of its clones are materialized, I had to make
sure that clones also get encode_body flag in the encoder (so that it
could be tested) and therefore in turn lto_output understands it needs
to skip clones.

This should actually mean less streaming in typical case because
previously we streamed three zeros for all nodes in a partition with
no useful information associated with them.  Currently we don't stream
anything for those.

When reworking the streaming, I also simplified it a little a
converted it writing to nicer C++ vector iterations.

gcc/ChangeLog:

2022-11-25  Martin Jambor  <mjambor@suse.cz>

	* ipa-prop.cc (useful_ipcp_transformation_info_p): New function.
	(write_ipcp_transformation_info): Added a parameter, simplified
	given that is known not to be NULL.
	(ipcp_write_transformation_summaries): Write out all useful
	transformation summaries.
	(read_ipcp_transformation_info): Simplify given that some info
	will be read.
	(read_replacements_section): Remove assert.
	* lto-cgraph.cc (add_node_to): Also set encode_body for clones.
	* lto-streamer-out.cc (lto_output): Do not output virtual clones.