diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index ce0ac90a24e..f864337629d 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2009-05-29  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/40291
+	* builtins.c (expand_builtin_memcmp): Convert len to sizetype
+	before expansion.
+
 2009-05-29  Andrey Belevantsev  <abel@ispras.ru>
 
 	PR rtl-optimization/40101
diff --git a/gcc/builtins.c b/gcc/builtins.c
index 783fce4ec68..6d9f2826689 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -4189,7 +4189,7 @@ expand_builtin_memcmp (tree exp, rtx target, enum machine_mode mode)
 
     arg1_rtx = get_memory_rtx (arg1, len);
     arg2_rtx = get_memory_rtx (arg2, len);
-    arg3_rtx = expand_normal (len);
+    arg3_rtx = expand_normal (fold_convert (sizetype, len));
 
     /* Set MEM_SIZE as appropriate.  */
     if (GET_CODE (arg3_rtx) == CONST_INT)
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 2c1fc0334f7..e8577143ff8 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,8 @@
 2009-05-29  Jakub Jelinek  <jakub@redhat.com>
 
+	PR middle-end/40291
+	* gcc.c-torture/compile/pr40291.c: New test.
+
 	PR target/40017
 	* gcc.target/powerpc/altivec-types-1.c: Don't expect error for
 	__vector _Bool.
@@ -22,7 +25,6 @@
 	* g++.dg/template/canon-type-6.C: Likewise.
 	* g++.dg/template/canon-type-7.C: Likewise.
 
-
 2009-05-28  Dave Korn  <dave.korn.cygwin@gmail.com>
             Uros Bizjak  <ubizjak@gmail.com>
             Danny Smith  <dansmister@gmail.com>
diff --git a/gcc/testsuite/gcc.c-torture/compile/pr40291.c b/gcc/testsuite/gcc.c-torture/compile/pr40291.c
new file mode 100644
index 00000000000..d50bbee6608
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr40291.c
@@ -0,0 +1,7 @@
+/* PR middle-end/40291 */
+
+int
+foo (void *x, char *y, unsigned long long z)
+{
+  return memcmp (x, y, z);
+}