Fix tramp3d PGO misoptimization

Fix tramp3d PGO misoptimization

this patch fixes tramp3d ICE with PGO.  It has turned out to be by a misupdate
in ignore_edge I introduced in previous patch that made us to not compute
SCCs correctly with -fno-lto.

While looking for problem I proofread the sources and also fortified the
srouces for situation where we insert a summary for no good reason and noticed
a problem that early ipa-modref disabled itself in some cases.
I also noticed that param_index is treamed as uhwi while it is signed (that
wastes file space).

Bootstrapping/regtesting x86_64-linux, will commit it tomorrow if that passes.

gcc/ChangeLog:

2020-10-13  Jan Hubicka  <hubicka@ucw.cz>

	PR ipa/97389
	* ipa-modref.c (dump_lto_records): Fix formating of dump file.
	(modref_summary::dump): Do not check loads to be non-null.
	(modref_summary_lto::dump): Do not check loads to be non-null.
	(merge_call_side_effects): Improve debug output.
	(analyze_call): Crash when cur_summary->loads is NULL.
	(analyze_function): Update.
	(modref_summaries::insert): Insert only into summaries, not
	optimization_summaries.
	(modref_summaries::duplicate): Likewise; crash when load or sotres
	are NULL.
	(modref_summaries_lto::duplicate): Crash when loads or stores are NULL.
	(write_modref_records): param_index is signed.
	(read_modref_records): param_index is signed.
	(modref_write): Crash when loads or stores are NULL.
	(read_section): Compensate previous change.
	(pass_modref::execute): Do not check optimization_summaries t be
	non-NULL.
	(ignore_edge): Fix.
	(compute_parm_map): Fix formating.
	(modref_propagate_in_scc): Do not expect loads/stores to be NULL.