diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index b20e8b23769..72a46cfefab 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2008-08-31  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/37289
+	* fold-const.c (fold_binary): Retain conversions in folding
+	~A + 1 to -A.
+
 2008-08-31  Jan Hubicka  <jh@suse.cz>
 
 	* postreload-gcse.c (eliminate_partially_redundant_loads): Use optimize_bb_for_size_p.
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index ae66ad4ee2d..561fb809314 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -9498,7 +9498,8 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
 	  /* Convert ~A + 1 to -A.  */
 	  if (TREE_CODE (arg0) == BIT_NOT_EXPR
 	      && integer_onep (arg1))
-	    return fold_build1 (NEGATE_EXPR, type, TREE_OPERAND (arg0, 0));
+	    return fold_build1 (NEGATE_EXPR, type,
+				fold_convert (type, TREE_OPERAND (arg0, 0)));
 
 	  /* ~X + X is -1.  */
 	  if (TREE_CODE (arg0) == BIT_NOT_EXPR
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index c03514ceee0..153c538fc9c 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2008-08-31  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/37289
+	* gcc.dg/pr37289.c: New testcase.
+
 2008-08-31  Jakub Jelinek  <jakub@redhat.com>
 
 	PR target/37168
diff --git a/gcc/testsuite/gcc.dg/pr37289.c b/gcc/testsuite/gcc.dg/pr37289.c
new file mode 100644
index 00000000000..61513c94ee2
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr37289.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-fdump-tree-original" } */
+
+void f(unsigned long x);
+
+void g(long x)
+{
+  f((unsigned long)(-1-x)+1);
+}
+
+/* Make sure we do not lose the conversion.  */
+
+/* { dg-final { scan-tree-dump "-\\\(long unsigned int\\\) x" "original" } } */
+/* { dg-final { cleanup-tree-dump "original" } } */