From d2a0371d2641e85c5e6ca396029be32204d976df Mon Sep 17 00:00:00 2001
From: Jan Hubicka <hubicka@ucw.cz>
Date: Sun, 14 Apr 2019 22:56:45 +0200
Subject: [PATCH] re PR lto/89358 (Combining -std=c++14 and -std=c++17 objects
 gives ODR warnings)

	PR lto/89358
	* g++.dg/lto/pr89358_0.C: New testcase.
	* g++.dg/lto/pr89358_1.C: New testcase.
	* ipa-devirt.c (skip_in_fields_list_p): New.
	(odr_types_equivalent_p): Use it.

From-SVN: r270355
---
 gcc/ChangeLog                        |  6 ++++++
 gcc/ipa-devirt.c                     | 22 ++++++++++++++++++++--
 gcc/testsuite/ChangeLog              |  6 ++++++
 gcc/testsuite/g++.dg/lto/pr89358_0.C | 11 +++++++++++
 gcc/testsuite/g++.dg/lto/pr89358_1.C |  7 +++++++
 5 files changed, 50 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/lto/pr89358_0.C
 create mode 100644 gcc/testsuite/g++.dg/lto/pr89358_1.C

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 6a394b8ce0f..a41417bbcbd 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2019-04-14  Jan Hubicka  <hubicka@ucw.cz>
+
+	PR lto/89358
+	* ipa-devirt.c (skip_in_fields_list_p): New.
+	(odr_types_equivalent_p): Use it.
+
 2019-04-13  Jakub Jelinek  <jakub@redhat.com>
 
 	PR target/89093
diff --git a/gcc/ipa-devirt.c b/gcc/ipa-devirt.c
index 61e4efc83d4..defa2ed3a5d 100644
--- a/gcc/ipa-devirt.c
+++ b/gcc/ipa-devirt.c
@@ -1282,6 +1282,24 @@ warn_types_mismatch (tree t1, tree t2, location_t loc1, location_t loc2)
     inform (loc_t2, "the incompatible type is defined here");
 }
 
+/* Return true if T should be ignored in TYPE_FIELDS for ODR comparsion.  */
+
+static bool
+skip_in_fields_list_p (tree t)
+{
+  if (TREE_CODE (t) != FIELD_DECL)
+    return true;
+  /* C++ FE introduces zero sized fields depending on -std setting, see
+     PR89358.  */
+  if (DECL_SIZE (t)
+      && integer_zerop (DECL_SIZE (t))
+      && DECL_ARTIFICIAL (t)
+      && DECL_IGNORED_P (t)
+      && !DECL_NAME (t))
+    return true;
+  return false;
+}
+
 /* Compare T1 and T2, report ODR violations if WARN is true and set
    WARNED to true if anything is reported.  Return true if types match.
    If true is returned, the types are also compatible in the sense of
@@ -1548,9 +1566,9 @@ odr_types_equivalent_p (tree t1, tree t2, bool warn, bool *warned,
 		 f1 = TREE_CHAIN (f1), f2 = TREE_CHAIN (f2))
 	      {
 		/* Skip non-fields.  */
-		while (f1 && TREE_CODE (f1) != FIELD_DECL)
+		while (f1 && skip_in_fields_list_p (f1))
 		  f1 = TREE_CHAIN (f1);
-		while (f2 && TREE_CODE (f2) != FIELD_DECL)
+		while (f2 && skip_in_fields_list_p (f2))
 		  f2 = TREE_CHAIN (f2);
 		if (!f1 || !f2)
 		  break;
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 0c4ae15ae9b..8055780aaa1 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2019-04-14  Jan Hubicka  <hubicka@ucw.cz>
+
+	PR lto/89358
+	* g++.dg/lto/pr89358_0.C: New testcase.
+	* g++.dg/lto/pr89358_1.C: New testcase.
+
 2019-04-14  Thomas Koenig  <tkoenig@gcc.gnu.org>
 
 	PR fortran/85448
diff --git a/gcc/testsuite/g++.dg/lto/pr89358_0.C b/gcc/testsuite/g++.dg/lto/pr89358_0.C
new file mode 100644
index 00000000000..aebd2127c0c
--- /dev/null
+++ b/gcc/testsuite/g++.dg/lto/pr89358_0.C
@@ -0,0 +1,11 @@
+/* { dg-do link } */
+/* { dg-options "-std=c++17"  } */
+#include <map>
+
+extern void test();
+
+int main()
+{
+        std::map<int, int> m;
+        test();
+}
diff --git a/gcc/testsuite/g++.dg/lto/pr89358_1.C b/gcc/testsuite/g++.dg/lto/pr89358_1.C
new file mode 100644
index 00000000000..68b80a37662
--- /dev/null
+++ b/gcc/testsuite/g++.dg/lto/pr89358_1.C
@@ -0,0 +1,7 @@
+/* { dg-options "-std=c++14"  } */
+#include <map>
+
+void test()
+{
+        std::map<int, int> m;
+}
-- 
2.30.2