re PR debug/51410 (duplicate variable DIE)

	PR debug/51410
	* c-decl.c (pop_scope): Don't add DECL_EXTERNAL decls
	for debug info if scope is file_scope.

	* gcc.dg/debug/dwarf2/pr51410.c: New test.

From-SVN: r182027

gcc/ChangeLog

 2011-12-05  Jakub Jelinek  <jakub@redhat.com>
 
+	PR debug/51410
+	* c-decl.c (pop_scope): Don't add DECL_EXTERNAL decls
+	for debug info if scope is file_scope.
+
 	PR c/51339
 	* c-decl.c (c_finish_incomplete_decl, finish_decl): Call
 	relayout_decl instead of layout_decl.

gcc/c-decl.c

@@ -1196,7 +1196,7 @@ pop_scope (void)
 	      DECL_CHAIN (p) = BLOCK_VARS (block);
 	      BLOCK_VARS (block) = p;
 	    }
-	  else if (VAR_OR_FUNCTION_DECL_P (p))
+	  else if (VAR_OR_FUNCTION_DECL_P (p) && scope != file_scope)
 	    {
 	      /* For block local externs add a special
 		 DECL_EXTERNAL decl for debug info generation.  */

gcc/testsuite/ChangeLog

 2011-12-05  Jakub Jelinek  <jakub@redhat.com>
 
+	PR debug/51410
+	* gcc.dg/debug/dwarf2/pr51410.c: New test.
+
 	PR c/51339
 	* gcc.dg/gomp/pr51339.c: New test.
 

gcc/testsuite/gcc.dg/debug/dwarf2/pr51410.c

+/* PR debug/51410 */
+/* { dg-do compile } */
+/* { dg-options "-O0 -gdwarf-2 -dA -fno-merge-debug-strings" } */
+
+int x;
+
+int
+foo (void)
+{
+  return x;
+}
+
+/* { dg-final { scan-assembler-times "\\(DIE\[^\\r\\n\]*DW_TAG_variable\\)" 1 } } */