diff --git a/glib/gslice.h b/glib/gslice.h
index ff8b02a65..002410635 100644
--- a/glib/gslice.h
+++ b/glib/gslice.h
@@ -23,6 +23,7 @@
 #endif
 
 #include <glib/gtypes.h>
+#include <string.h>
 
 G_BEGIN_DECLS
 
@@ -43,7 +44,22 @@ void     g_slice_free_chain_with_offset (gsize         block_size,
 					 gpointer      mem_chain,
 					 gsize         next_offset);
 #define  g_slice_new(type)      ((type*) g_slice_alloc (sizeof (type)))
-#define  g_slice_new0(type)     ((type*) g_slice_alloc0 (sizeof (type)))
+
+/* Allow the compiler to inline memset(). Since the size is a constant, this
+ * can significantly improve performance. */
+#if defined (__GNUC__) && (__GNUC__ >= 2) && defined (__OPTIMIZE__)
+#  define g_slice_new0(type)                                    \
+  (type *) (G_GNUC_EXTENSION ({                                 \
+    gsize __s = sizeof (type);                                  \
+    gpointer __p;                                               \
+    __p = g_slice_alloc (__s);                                  \
+    memset (__p, 0, __s);                                       \
+    __p;                                                        \
+  }))
+#else
+#  define g_slice_new0(type)    ((type*) g_slice_alloc0 (sizeof (type)))
+#endif
+
 /* MemoryBlockType *
  *       g_slice_dup                    (MemoryBlockType,
  *	                                 MemoryBlockType *mem_block);