From 0589be0c59767cf4cbb0ef0e7d918cf6aa3d606c Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Tue, 13 Apr 2021 20:32:13 -0400
Subject: [PATCH] c++: DWARF ICE with defaulted specialization [PR90674]

Here when we merged the specialization with the implicit instantiation
declaration, we wrongly kept the value of DECL_INITIALIZED_IN_CLASS_P from
the latter.

gcc/cp/ChangeLog:

	PR c++/90674
	* decl.c (duplicate_decls): Don't propagate
	DECL_INITIALIZED_IN_CLASS_P to a specialization.

gcc/testsuite/ChangeLog:

	PR c++/90674
	* g++.dg/debug/defaulted1.C: New test.
---
 gcc/cp/decl.c                           |  5 +++--
 gcc/testsuite/g++.dg/debug/defaulted1.C | 10 ++++++++++
 2 files changed, 13 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/debug/defaulted1.C

diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index ec05ee1f0b49..1cb473139238 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -2556,8 +2556,9 @@ duplicate_decls (tree newdecl, tree olddecl, bool hiding, bool was_hidden)
 	  if (!DECL_USE_TEMPLATE (newdecl))
 	    DECL_USE_TEMPLATE (newdecl) = DECL_USE_TEMPLATE (olddecl);
 
-	  DECL_INITIALIZED_IN_CLASS_P (newdecl)
-	    |= DECL_INITIALIZED_IN_CLASS_P (olddecl);
+	  if (!DECL_TEMPLATE_SPECIALIZATION (newdecl))
+	    DECL_INITIALIZED_IN_CLASS_P (newdecl)
+	      |= DECL_INITIALIZED_IN_CLASS_P (olddecl);
 	}
 
       /* Don't really know how much of the language-specific
diff --git a/gcc/testsuite/g++.dg/debug/defaulted1.C b/gcc/testsuite/g++.dg/debug/defaulted1.C
new file mode 100644
index 000000000000..3ea7ae72b96b
--- /dev/null
+++ b/gcc/testsuite/g++.dg/debug/defaulted1.C
@@ -0,0 +1,10 @@
+// PR c++/90674
+// { dg-do compile { target c++11 } }
+
+template<typename T>
+struct C {
+    C() {}
+};
+
+template<>
+C<int>::C() = default;
-- 
2.47.2