patch 9.1.0701: crash with NFA regex engine when searching for composing chars

Problem:  crash with NFA regex engine when searching for composing chars
          (SuyueGuo)
Solution: When there is no composing character, break out of the loop
          and check that out1 state is not null

fixes: #15583

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/regexp_nfa.c b/src/regexp_nfa.c
index 6db4134..557d0e1 100644
--- a/src/regexp_nfa.c
+++ b/src/regexp_nfa.c
@@ -6525,7 +6525,8 @@
 			else
 			    result = FAIL;
 
-			if (t->state->out->out1->c == NFA_END_COMPOSING)
+			if (t->state->out->out1 != NULL
+				&& t->state->out->out1->c == NFA_END_COMPOSING)
 			{
 			    end = t->state->out->out1;
 			    ADD_STATE_IF_MATCH(end);
diff --git a/src/testdir/crash/nullptr_regexp_nfa b/src/testdir/crash/nullptr_regexp_nfa
new file mode 100644
index 0000000..6b2edc6
--- /dev/null
+++ b/src/testdir/crash/nullptr_regexp_nfa
Binary files differ
diff --git a/src/testdir/test_crash.vim b/src/testdir/test_crash.vim
index e741a18..bfd04ff 100644
--- a/src/testdir/test_crash.vim
+++ b/src/testdir/test_crash.vim
@@ -228,6 +228,11 @@
   call term_sendkeys(buf, args)
   call TermWait(buf, 50)
 
+  let file = 'crash/nullptr_regexp_nfa'
+  let cmn_args = "%s -u NONE -i NONE -n -X -m -n -e -s -S %s -c ':qa!'"
+  let args = printf(cmn_args, vim, file)
+  call term_sendkeys(buf, args)
+  call TermWait(buf, 50)
 
   " clean up
   exe buf .. "bw!"
diff --git a/src/version.c b/src/version.c
index 59bd3fc..5dfb313 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    701,
+/**/
     700,
 /**/
     699,