diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 974af002d5ea..7c60f7eeeb48 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2011-12-19  Martin Jambor  <mjambor@suse.cz>
+
+	PR tree-optimization/51583
+	* tree-sra.c (load_assign_lhs_subreplacements): Call
+	force_gimple_operand_gsi when necessary also in case of no
+	corresponding replacement on the RHS.
+
 2011-12-19  Jakub Jelinek  <jakub@redhat.com>
 
 	* gimple.h (gimplify_seq_add_stmt): Rename to...
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index a7c1c48a37cf..b1a3762b4751 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2011-12-19  Martin Jambor  <mjambor@suse.cz>
+
+	PR tree-optimization/51583
+	* gcc.dg/tree-ssa/pr51583.c: New test.
+
 2011-12-19  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/51596
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr51583.c b/gcc/testsuite/gcc.dg/tree-ssa/pr51583.c
new file mode 100644
index 000000000000..2c4ec4723c47
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr51583.c
@@ -0,0 +1,34 @@
+/* { dg-do compile } */
+/* { dg-options "-O1" } */
+
+typedef __complex__ double Value;
+
+union U
+{
+  Value v;
+  char c[sizeof(Value)];
+};
+
+struct S
+{
+  union U u;
+  int i,j;
+};
+
+Value gv;
+int gi, gj;
+
+Value foo (void)
+{
+  struct S s,t;
+
+  t.i = gi;
+  t.j = gj;
+  t.u.v = gv;
+  t.u.c[0] = 0;
+
+  s = t;
+  __imag__ s.u.v += s.i;
+
+  return s.u.v;
+}
diff --git a/gcc/tree-sra.c b/gcc/tree-sra.c
index 84cbc8462149..db9b9bf44523 100644
--- a/gcc/tree-sra.c
+++ b/gcc/tree-sra.c
@@ -2752,6 +2752,9 @@ load_assign_lhs_subreplacements (struct access *lacc, struct access *top_racc,
 	      else
 		rhs = build_ref_for_model (loc, top_racc->base, offset, lacc,
 					    new_gsi, true);
+	      if (lacc->grp_partial_lhs)
+		rhs = force_gimple_operand_gsi (new_gsi, rhs, true, NULL_TREE,
+						false, GSI_NEW_STMT);
 	    }
 
 	  stmt = gimple_build_assign (get_access_replacement (lacc), rhs);