diff --git a/src/diff.c b/src/diff.c
index c50670c..70e2814 100644
--- a/src/diff.c
+++ b/src/diff.c
@@ -760,6 +760,13 @@
     long	len = 0;
     char_u	*ptr;
 
+    if (buf->b_ml.ml_flags & ML_EMPTY)
+    {
+	din->din_mmfile.ptr = NULL;
+	din->din_mmfile.size = 0;
+	return OK;
+    }
+
     // xdiff requires one big block of memory with all the text.
     for (lnum = 1; lnum <= buf->b_ml.ml_line_count; ++lnum)
 	len += ml_get_buf_len(buf, lnum) + 1;
diff --git a/src/testdir/dumps/Test_diff_21.dump b/src/testdir/dumps/Test_diff_21.dump
new file mode 100644
index 0000000..8fc8c6c
--- /dev/null
+++ b/src/testdir/dumps/Test_diff_21.dump
@@ -0,0 +1,20 @@
+| +0#0000e05#a8a8a8255@1|0+0#0000000#5fd7ff255| @33||+1&#ffffff0| +0#0000e05#a8a8a8255@1|-+0#4040ff13#afffff255@34
+|~+0&#ffffff0| @35||+1#0000000&| +0#0000e05#a8a8a8255@1| +0#0000000#ffffff0@34
+|~+0#4040ff13&| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|X+3#0000000&|d|i|f|i|l|e|1| @10|1|,|1| @11|A|l@1| |X+1&&|d|i|f|i|l|e|2| @10|0|,|0|-|1| @9|A|l@1
+|:+0&&> @73
diff --git a/src/testdir/dumps/Test_diff_22.dump b/src/testdir/dumps/Test_diff_22.dump
new file mode 100644
index 0000000..5ab9ae2
--- /dev/null
+++ b/src/testdir/dumps/Test_diff_22.dump
@@ -0,0 +1,20 @@
+| +0#0000e05#a8a8a8255@1|-+0#4040ff13#afffff255@34||+1#0000000#ffffff0| +0#0000e05#a8a8a8255@1|0+0#0000000#5fd7ff255| @33
+| +0#0000e05#a8a8a8255@1| +0#0000000#ffffff0@34||+1&&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|X+3#0000000&|d|i|f|i|l|e|1| @10|0|,|0|-|1| @9|A|l@1| |X+1&&|d|i|f|i|l|e|2| @10|1|,|1| @11|A|l@1
+|:+0&&> @73
diff --git a/src/testdir/test_diffmode.vim b/src/testdir/test_diffmode.vim
index 098d5d0..c391f2d 100644
--- a/src/testdir/test_diffmode.vim
+++ b/src/testdir/test_diffmode.vim
Binary files differ
diff --git a/src/version.c b/src/version.c
index f4b7554..4669e37 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    740,
+/**/
     739,
 /**/
     738,