[PATCH] Recognize clones for all contexts in SCCs in IPA-CP

[Jan Hubicka]

> Hi,
> 
> in IPA-CP, a few functions look at callees of cgraph edges to see if
> they still lead to the original node (those still need to be examined
> or re-examined) or to a clone (those are considered already decided
> and should be left alone).  The problem is that currently, when
> looking at an SCC, these functions decide not to "close" the SCC by
> switching the last edge from a specialized clone to a specialized
> clone because it already leads to a clone, albeit one for all
> contexts.
> 
> In the testcase ipcp-agg-7.c that is part of this patch, this leads to
> two copies of foo, one of them not specialized for known aggregate
> values, even though there should have been just one.
> 
> The patch fixes this by introducing another flag is_all_contexts_clone
> and testing it in the necessary functions.  In order to avoid
> confusion, I renamed already existing flag clone_for_all_contexts to
> do_clone_for_all_contexts.
> 
> Additionally, I discovered that decide_whether_version_node contains a
> bogus "|| !plats->aggs" in a test, which is harmless but just should
> not be there, so I removed it.
> 
> Bootstrapped and tested on x86_64-linux.  OK for trunk?
> 
> Martin
> 
> 
> 2012-11-20  Martin Jambor  <mjambor@suse.cz>
> 
> 	* ipa-prop.h (struct ipa_node_params): Rename clone_for_all_contexts to
> 	do_clone_for_all_contexts.  Update all uses.  New flag
> 	is_all_contexts_clone.
> 
> 	* ipa-cp.c (cgraph_edge_brings_value_p): Also consider the case when cs
> 	leads to the clone for all contexts.
> 	(perhaps_add_new_callers): Likewise.
> 	(decide_whether_version_node): Remove bogus !plats->aggs test.  Set
> 	is_all_contexts_clone when cloning for all contexts.
> 
> 	* testsuite/gcc.dg/ipa/ipcp-agg-7.c: New test.
> 	* testsuite/gcc.dg/ipa/ipcp-agg-8.c: Likewise.

OK,
thanks!
Honza