[gcc(refs/users/ppalka/heads/libstdcxx-constrained-algos)] [PR90916] ICE in retrieve specialization

[Patrick Palka]

https://gcc.gnu.org/g:a5a3c2dcf73aa245b0eb6f6cf56c4d03ab6056da

commit a5a3c2dcf73aa245b0eb6f6cf56c4d03ab6056da
Author: Nathan Sidwell <nathans@fb.com>
Date:   Tue Jan 14 11:12:40 2020 -0800

    [PR90916] ICE in retrieve specialization
    
    https://gcc.gnu.org/ml/gcc-patches/2020-01/msg00809.html
    	PR c++/90916
    	* pt.c (retrieve_specialization): Get the TI from the decl or the
    	classtype as appropriate.

Diff:
---
 gcc/cp/ChangeLog                        |  6 ++++++
 gcc/cp/pt.c                             | 15 ++++++++++-----
 gcc/testsuite/g++.dg/template/pr90916.C |  8 ++++++++
 3 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 004ce0f..3cc7c48 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2020-01-14  Nathan Sidwell  <nathan@acm.org>
+
+	PR c++/90916
+	* pt.c (retrieve_specialization): Get the TI from the decl or the
+	classtype as appropriate.
+
 2020-01-14  David Malcolm  <dmalcolm@redhat.com>
 
 	* cp-gimplify.c (source_location_table_entry_hash::empty_zero_p):
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index fa82eca..4fdc74f 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -1252,11 +1252,16 @@ retrieve_specialization (tree tmpl, tree args, hashval_t hash)
       for (ovl_iterator iter (fns); iter; ++iter)
 	{
 	  tree fn = *iter;
-	  if (DECL_TEMPLATE_INFO (fn) && DECL_TI_TEMPLATE (fn) == tmpl
-	      /* using-declarations can add base methods to the method vec,
-		 and we don't want those here.  */
-	      && DECL_CONTEXT (fn) == class_specialization)
-	    return fn;
+	  if (tree ti = (TREE_CODE (fn) == TYPE_DECL && !TYPE_DECL_ALIAS_P (fn)
+			 ? TYPE_TEMPLATE_INFO (TREE_TYPE (fn))
+			 : DECL_TEMPLATE_INFO (fn)))
+	    if (TI_TEMPLATE (ti) == tmpl
+		/* using-declarations can bring in a different
+		   instantiation of tmpl as a member of a different
+		   instantiation of tmpl's class.  We don't want those
+		   here.  */
+		&& DECL_CONTEXT (fn) == class_specialization)
+	      return fn;
 	}
       return NULL_TREE;
     }
diff --git a/gcc/testsuite/g++.dg/template/pr90916.C b/gcc/testsuite/g++.dg/template/pr90916.C
new file mode 100644
index 0000000..bdb7e7b
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/pr90916.C
@@ -0,0 +1,8 @@
+// PR c++/90916 ICE in retrieve_specialization
+
+template <typename> struct S
+{
+  struct A;
+  struct f A ();
+};
+template class S <int>;