"git diff --no-index" beheviour on special files

gistfile1.txt

$ diff -ur  <(printf 'a\nb\nc\n') <(printf 'a\nd\nc\n')
--- /dev/fd/63	2012-03-08 02:27:23.088325870 +0300
+++ /dev/fd/62	2012-03-08 02:27:23.088325870 +0300
@@ -1,3 +1,3 @@
 a
-b
+d
 c
$ git diff --no-index  <(printf 'a\nb\nc\n') <(printf 'a\nd\nc\n')
diff --git a/dev/fd/63 b/dev/fd/62
index 33d340f..1b195c6 120000
--- a/dev/fd/63
+++ b/dev/fd/62
@@ -1 +1 @@
-pipe:[599532]
\ No newline at end of file
+pipe:[599534]
\ No newline at end of file