cgraph: Don't verify semantic_interposition flag for aliases [PR105399]

The following testcase ICEs, because the ctors during cc1plus all have
!opt_for_fn (decl, flag_semantic_interposition) - they have NULL
DECL_FUNCTION_SPECIFIC_OPTIMIZATION (decl) and optimization_default_node
is for -Ofast and so has flag_semantic_interposition cleared.
During free lang data, we set DECL_FUNCTION_SPECIFIC_OPTIMIZATION (decl)
for the ctor which has body (or for thunks), but don't touch it for
aliases.
During lto1 optimization_default_node reflects the lto1 flags which
are -O2 rather than -Ofast and so has flag_semantic_interposition
set, for the ctor which has body that makes no difference, but as the
alias doesn't still have DECL_FUNCTION_SPECIFIC_OPTIMIZATION (decl) set,
we now trigger this verification check.

The following patch just doesn't verify it for aliases during lto1.
Another possibility would be to set DECL_FUNCTION_SPECIFIC_OPTIMIZATION (decl)
during free lang data even for aliases.

2022-04-28  Jakub Jelinek  <jakub@redhat.com>

	PR lto/105399
	* cgraph.cc (cgraph_node::verify_node): Don't verify
	semantic_interposition flag against
	opt_for_fn (decl, flag_semantic_interposition) for aliases in lto1.

	* g++.dg/lto/pr105399_0.C: New test.

diff --git a/gcc/cgraph.cc b/gcc/cgraph.cc
index d3cc06b..0159eaa 100644 (file)
--- a/gcc/cgraph.cc
+++ b/gcc/cgraph.cc
@@ -3488,7 +3488,11 @@ cgraph_node::verify_node (void)
             "returns a pointer");
       error_found = true;
     }
-  if (definition && externally_visible
+  if (definition
+      && externally_visible
+      /* For aliases in lto1 free_lang_data doesn't guarantee preservation
+        of opt_for_fn (decl, flag_semantic_interposition).  See PR105399.  */
+      && (!alias || !in_lto_p)
       && semantic_interposition
         != opt_for_fn (decl, flag_semantic_interposition))
     {

diff --git a/gcc/testsuite/g++.dg/lto/pr105399_0.C b/gcc/testsuite/g++.dg/lto/pr105399_0.C
new file mode 100644 (file)
index 0000000..fc9149a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/lto/pr105399_0.C
@@ -0,0 +1,9 @@
+// PR lto/105399
+// { dg-lto-do link }
+// { dg-lto-options { { -fPIC -flto -Ofast } } }
+// { dg-require-effective-target shared }
+// { dg-require-effective-target fpic }
+// { dg-extra-ld-options "-shared -O2" }
+
+struct S { S (); };
+S::S () {}