diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index f44708140de..41c09ff5a61 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2011-02-18  Jakub Jelinek  <jakub@redhat.com>
+
+	PR debug/47780
+	* cfgexpand.c (expand_debug_expr) <case SSA_NAME>: Call copy_rtx to
+	avoid invalid rtx sharing.
+
 2011-02-18  Gerald Pfeifer  <gerald@pfeifer.com>
 
 	* doc/cpp.texi (Obsolete Features): Add background on the
diff --git a/gcc/cfgexpand.c b/gcc/cfgexpand.c
index 897d0f9f2b3..ee51ba9f9c0 100644
--- a/gcc/cfgexpand.c
+++ b/gcc/cfgexpand.c
@@ -3104,7 +3104,7 @@ expand_debug_expr (tree exp)
 
 	    gcc_assert (part >= 0 && (unsigned)part < SA.map->num_partitions);
 
-	    op0 = SA.partition_to_pseudo[part];
+	    op0 = copy_rtx (SA.partition_to_pseudo[part]);
 	  }
 	goto adjust_mode;
       }
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 998cfc211fa..40e2553cfc7 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2011-02-18  Jakub Jelinek  <jakub@redhat.com>
+
+	PR debug/47780
+	* gcc.target/i386/pr47780.c: New test.
+
 2011-02-18  Janus Weil  <janus@gcc.gnu.org>
 
 	PR fortran/47767
diff --git a/gcc/testsuite/gcc.target/i386/pr47780.c b/gcc/testsuite/gcc.target/i386/pr47780.c
new file mode 100644
index 00000000000..89fe4093dfc
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr47780.c
@@ -0,0 +1,14 @@
+/* PR debug/47780 */
+/* { dg-do compile } */
+/* { dg-options "-O -fgcse -fgcse-las -fstack-protector-all -fno-tree-ccp -fno-tree-dominator-opts -fcompare-debug -Wno-psabi" } */
+
+typedef int V2SF __attribute__ ((vector_size (128)));
+
+V2SF
+foo (int x, V2SF a)
+{
+  V2SF b = a + (V2SF) {};
+  while (x--)
+    a += b;
+  return a;
+}