ipa: target clone and mangling alias [PR114992]

Since the mangling of the second lambda changed (previously we counted all
lambdas, now we only count lambdas with the same signature), we
generate_mangling_alias for handler<lambda2> for backward compatibility.
Since handler is COMDAT, resolve_alias puts the alias in the same comdat
group as handler itself.  Then create_dispatcher_calls tries to add the
alias to the same comdat group as the dispatcher, but it's already in a
same_comdat_group, so we ICE.

It seems like we're just missing a remove_from_same_comdat_group before
add_to_same_comdat_group.

	PR c++/114992

gcc/ChangeLog:

	* multiple_target.cc (create_dispatcher_calls):
	remove_from_same_comdat_group before add_to_same_comdat_group.

gcc/testsuite/ChangeLog:

	* g++.target/i386/mangling-alias1.C: New test.

(cherry picked from commit ab716829da7c885b97ac2649c7c0ff5c7703ffa5)

diff --git a/gcc/multiple_target.cc b/gcc/multiple_target.cc
index 60958a56c92dfb2b536816f1201730605a6c08c5..b173044cbee18a0a92c4558a96c8cb4ead8b330b 100644 (file)
--- a/gcc/multiple_target.cc
+++ b/gcc/multiple_target.cc
@@ -155,7 +155,11 @@ create_dispatcher_calls (struct cgraph_node *node)
              symtab_node *source = ref->referring;
              source->create_reference (inode, IPA_REF_ALIAS);
              if (inode->get_comdat_group ())
-               source->add_to_same_comdat_group (inode);
+               {
+                 if (source->same_comdat_group)
+                   source->remove_from_same_comdat_group ();
+                 source->add_to_same_comdat_group (inode);
+               }
            }
          else
            gcc_unreachable ();

diff --git a/gcc/testsuite/g++.target/i386/mangling-alias1.C b/gcc/testsuite/g++.target/i386/mangling-alias1.C
new file mode 100644 (file)
index 0000000..70264e2
--- /dev/null
+++ b/gcc/testsuite/g++.target/i386/mangling-alias1.C
@@ -0,0 +1,16 @@
+// PR c++/114992
+// { dg-do compile { target { c++11 && x86_64-*-* } } }
+// { dg-require-ifunc }
+
+template <typename Callable>
+__attribute__((target_clones("avx2", "default")))
+void handler(Callable) {}
+
+inline int func()
+{
+  auto l1 = [](int) {}; // different lambda signature
+  handler([]() {}); // so this one needs a mangling alias
+  return 42;
+}
+
+int g = func();