From: Martin Liska <mliska@suse.cz>
Date: Wed, 7 Mar 2018 09:47:46 +0000 (+0100)
Subject: Backport r256989
X-Git-Tag: releases/gcc-6.5.0~469
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7fefe0141dc81d1c2bae33015133a061bda5ea9b;p=thirdparty%2Fgcc.git

Backport r256989

2018-03-07  Martin Liska  <mliska@suse.cz>

	Backport from mainline
	2018-01-23  Martin Liska  <mliska@suse.cz>

	PR lto/81440
	* lto-symtab.c (lto_symtab_merge): Handle and do not warn about
	trailing arrays at the end of a struct.
2018-03-07  Martin Liska  <mliska@suse.cz>

	Backport from mainline
	2018-01-23  Martin Liska  <mliska@suse.cz>

	PR lto/81440
	* gcc.dg/lto/pr81440.h: New test.
	* gcc.dg/lto/pr81440_0.c: New test.
	* gcc.dg/lto/pr81440_1.c: New test.

From-SVN: r258328
---

diff --git a/gcc/lto/ChangeLog b/gcc/lto/ChangeLog
index 2d016a96ea1a..c755b383d6d9 100644
--- a/gcc/lto/ChangeLog
+++ b/gcc/lto/ChangeLog
@@ -1,3 +1,12 @@
+2018-03-07  Martin Liska  <mliska@suse.cz>
+
+	Backport from mainline
+	2018-01-23  Martin Liska  <mliska@suse.cz>
+
+	PR lto/81440
+	* lto-symtab.c (lto_symtab_merge): Handle and do not warn about
+	trailing arrays at the end of a struct.
+
 2018-03-07  Martin Liska  <mliska@suse.cz>
 
 	Backport from mainline
diff --git a/gcc/lto/lto-symtab.c b/gcc/lto/lto-symtab.c
index e6fb95fe3729..6b3b785b674f 100644
--- a/gcc/lto/lto-symtab.c
+++ b/gcc/lto/lto-symtab.c
@@ -362,18 +362,31 @@ lto_symtab_merge (symtab_node *prevailing, symtab_node *entry)
     return false;
 
   if (DECL_SIZE (decl) && DECL_SIZE (prevailing_decl)
-      && !tree_int_cst_equal (DECL_SIZE (decl), DECL_SIZE (prevailing_decl))
+      && !tree_int_cst_equal (DECL_SIZE (decl), DECL_SIZE (prevailing_decl)))
+      {
+	if (!DECL_COMMON (decl) && !DECL_EXTERNAL (decl))
+	  return false;
+
+	tree type = TREE_TYPE (decl);
+
+	/* For record type, check for array at the end of the structure.  */
+	if (TREE_CODE (type) == RECORD_TYPE)
+	  {
+	    tree field = TYPE_FIELDS (type);
+	    while (DECL_CHAIN (field) != NULL_TREE)
+	      field = DECL_CHAIN (field);
+
+	    return TREE_CODE (TREE_TYPE (field)) == ARRAY_TYPE;
+	  }
       /* As a special case do not warn about merging
 	 int a[];
 	 and
 	 int a[]={1,2,3};
 	 here the first declaration is COMMON
 	 and sizeof(a) == sizeof (int).  */
-      && ((!DECL_COMMON (decl) && !DECL_EXTERNAL (decl))
-	  || TREE_CODE (TREE_TYPE (decl)) != ARRAY_TYPE
-	  || TYPE_SIZE (TREE_TYPE (decl))
-	     != TYPE_SIZE (TREE_TYPE (TREE_TYPE (decl)))))
-    return false;
+	else if (TREE_CODE (type) == ARRAY_TYPE)
+	  return (TYPE_SIZE (decl) == TYPE_SIZE (TREE_TYPE (type)));
+      }
 
   return true;
 }
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index e19c92e95487..2d75729f2961 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,13 @@
+2018-03-07  Martin Liska  <mliska@suse.cz>
+
+	Backport from mainline
+	2018-01-23  Martin Liska  <mliska@suse.cz>
+
+	PR lto/81440
+	* gcc.dg/lto/pr81440.h: New test.
+	* gcc.dg/lto/pr81440_0.c: New test.
+	* gcc.dg/lto/pr81440_1.c: New test.
+
 2018-03-07  Martin Liska  <mliska@suse.cz>
 
 	Backport from mainline
diff --git a/gcc/testsuite/gcc.dg/lto/pr81440.h b/gcc/testsuite/gcc.dg/lto/pr81440.h
new file mode 100644
index 000000000000..d9e6c3da6459
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/lto/pr81440.h
@@ -0,0 +1,4 @@
+typedef struct {
+  int i;
+  int ints[];
+} struct_t;
diff --git a/gcc/testsuite/gcc.dg/lto/pr81440_0.c b/gcc/testsuite/gcc.dg/lto/pr81440_0.c
new file mode 100644
index 000000000000..07f2a87da21a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/lto/pr81440_0.c
@@ -0,0 +1,9 @@
+/* { dg-lto-do link } */
+
+#include "pr81440.h"
+
+extern struct_t my_struct;
+
+int main() {
+ return my_struct.ints[0];
+}
diff --git a/gcc/testsuite/gcc.dg/lto/pr81440_1.c b/gcc/testsuite/gcc.dg/lto/pr81440_1.c
new file mode 100644
index 000000000000..d03533029c1e
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/lto/pr81440_1.c
@@ -0,0 +1,6 @@
+#include "pr81440.h"
+
+struct_t my_struct = {
+ 20,
+ { 1, 2 }
+};