From: Jakub Jelinek <jakub@redhat.com>
Date: Fri, 20 Dec 2019 17:26:28 +0000 (+0100)
Subject: backport: re PR c++/92695 (P1064R0 - virtual constexpr fails if object taken from... 
X-Git-Tag: releases/gcc-9.3.0~292
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e3edafbca9f3553ff95f3e083d9e5b67ff141ba3;p=thirdparty%2Fgcc.git

backport: re PR c++/92695 (P1064R0 - virtual constexpr fails if object taken from array)

	Backported from mainline
	2019-11-28  Jakub Jelinek  <jakub@redhat.com>

	PR c++/92695
	* decl2.c (mark_used): Don't call note_vague_linkage_fn for pure
	virtual functions, even if they are declared inline.

	* g++.dg/warn/inline3.C: New test.

From-SVN: r279661
---

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 83a9adc288a8..d95f679907e2 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,6 +1,12 @@
 2019-12-20  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2019-11-28  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/92695
+	* decl2.c (mark_used): Don't call note_vague_linkage_fn for pure
+	virtual functions, even if they are declared inline.
+
 	2019-11-27  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/92524
diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c
index 6f23ee1cd3fe..a46cbce08f4d 100644
--- a/gcc/cp/decl2.c
+++ b/gcc/cp/decl2.c
@@ -5501,8 +5501,11 @@ mark_used (tree decl, tsubst_flags_t complain)
 	vec_safe_push (no_linkage_decls, decl);
     }
 
-  if (TREE_CODE (decl) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (decl)
-      && !DECL_INITIAL (decl) && !DECL_ARTIFICIAL (decl))
+  if (TREE_CODE (decl) == FUNCTION_DECL
+      && DECL_DECLARED_INLINE_P (decl)
+      && !DECL_INITIAL (decl)
+      && !DECL_ARTIFICIAL (decl)
+      && !DECL_PURE_VIRTUAL_P (decl))
     /* Remember it, so we can check it was defined.  */
     note_vague_linkage_fn (decl);
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index b10c2e057690..eb6108b3a3ed 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,6 +1,11 @@
 2019-12-20  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2019-11-28  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/92695
+	* g++.dg/warn/inline3.C: New test.
+
 	2019-11-27  Jakub Jelinek  <jakub@redhat.com>
 
 	PR fortran/91944
diff --git a/gcc/testsuite/g++.dg/warn/inline3.C b/gcc/testsuite/g++.dg/warn/inline3.C
new file mode 100644
index 000000000000..0d4dc8ff2685
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/inline3.C
@@ -0,0 +1,20 @@
+struct S {
+  inline virtual void foo () = 0;	// { dg-bogus "used but never defined" }
+#if __cplusplus > 201703L
+  constexpr virtual void bar () = 0;	// { dg-bogus "used but never defined" "" { target c++2a } }
+#else
+  inline virtual void bar () = 0;	// { dg-bogus "used but never defined" "" { target c++17_down }  }
+#endif
+  S () {}
+};
+struct T : public S {
+  inline virtual void foo () {}
+#if __cplusplus > 201703L
+  constexpr virtual void bar () {}
+#else
+  inline virtual void bar () {}
+#endif
+  T () {}
+};
+T t;
+void foo (S *s) { s->foo (); s->bar (); }