On Fri, Nov 21, 2014 at 10:59 AM, Martin Jambor <mjam...@suse.cz> wrote:
> Hi,
>
> PR 63814 is caused by cgraph_edge_brings_value_p misidentifying an
> edge to an expanded artificial thunk as an edge to the original node,
> which then leads to crazy double-cloning and doubling the thunks along
> the call.
>
> This patch fixes the bug by strengthening the predicate so that it
> knows where the value is supposed to go and can check that it goes
> there and not anywhere else. It also adds an extra availability check
> that was probably missing in it.
>
> Bootstrapped and tested on x86_64-linux, and i686-linux. OK for
> trunk?
>
> Thanks,
>
> Martin
>
>
> 2014-11-20 Martin Jambor <mjam...@suse.cz>
>
> PR ipa/63814
> * ipa-cp.c (same_node_or_its_all_contexts_clone_p): New function.
> (cgraph_edge_brings_value_p): New parameter dest, use
> same_node_or_its_all_contexts_clone_p and check availability.
> (cgraph_edge_brings_value_p): Likewise.
> (get_info_about_necessary_edges): New parameter dest, pass it to
> cgraph_edge_brings_value_p. Update caller.
> (gather_edges_for_value): Likewise.
> (perhaps_add_new_callers): Use cgraph_edge_brings_value_p to check
> both the destination and availability.
>
>
I checked in this testcase:
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index a17cc6c..1410f10 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2014-12-02 H.J. Lu <hongjiu...@intel.com>
+
+ PR ipa/63814
+ * g++.dg/ipa/pr63814.C: New test.
+
2014-12-02 Wilco Dijkstra <wilco.dijks...@arm.com>
* gcc.target/aarch64/remat1.c: New testcase.
diff --git a/gcc/testsuite/g++.dg/ipa/pr63814.C
b/gcc/testsuite/g++.dg/ipa/pr63814.C
new file mode 100644
index 0000000..15a7dda
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ipa/pr63814.C
@@ -0,0 +1,29 @@
+// { dg-do run { target fpic } }
+// { dg-options "-O3 -fpic" }
+
+struct CBase {
+ virtual void BaseFunc () {}
+};
+
+struct MMixin {
+ virtual void * MixinFunc (int, int) = 0;
+};
+
+struct CExample: CBase, public MMixin
+{
+ void *MixinFunc (int arg, int arg2)
+ {
+ return this;
+ }
+};
+
+void *test (MMixin & anExample)
+{
+ return anExample.MixinFunc (0, 0);
+}
+
+int main ()
+{
+ CExample c;
+ return (test (c) != &c);
+}
H.J.
