diff --git a/Lib/test/test_re.py b/Lib/test/test_re.py
index 1eca22f45378df1..5b534c703a1f52e 100644
--- a/Lib/test/test_re.py
+++ b/Lib/test/test_re.py
@@ -502,6 +502,65 @@ def test_bug_117612(self):
         self.assertEqual(re.findall(r"(a|(b))", "aba"),
                          [("a", ""),("b", "b"),("a", "")])
 
+    def test_bug_7940(self):
+        # Issue 7940: re.finditer and re.findall should support negative end positions
+        pat = re.compile(".")
+
+        with self.assertWarns(FutureWarning) as cm:
+            self.assertEqual(pat.findall("abcd", -1, 1), [])
+        self.assertEqual(str(cm.warning), "Negative start index will not "
+                         "be truncated to zero in the future")
+
+        with self.assertWarns(FutureWarning) as cm:
+            self.assertEqual(pat.findall("abcd", 1, -1), ['b', 'c'])
+        self.assertEqual(str(cm.warning), "Negative end index will not "
+                         "be truncated to zero in the future")
+
+        with self.assertWarns(FutureWarning) as cm:
+            self.assertEqual(pat.findall("abcd", 1, 3), ['b', 'c'])
+            self.assertEqual(pat.findall("abcd", 1, -1), ['b', 'c'])
+            self.assertEqual(pat.findall("abcd", -3, -1), ['b', 'c'])
+            self.assertEqual(pat.findall("abcd", -3, 3), ['b', 'c'])
+            self.assertEqual(pat.findall("abcd", -1, 1), [])
+            self.assertEqual(pat.findall("abcd", -1, -3), [])
+            self.assertEqual(pat.findall("abcd", -200, -1), ['a', 'b', 'c'])
+            self.assertEqual(pat.findall("abcd", -200, -100), [])
+            self.assertEqual(pat.findall("abcd", pos=1, endpos=-1), ['b', 'c'])
+        self.assertEqual(len(cm.warnings), 12)
+
+        with self.assertWarns(FutureWarning) as cm:
+            self.assertEqual([m[0] for m in pat.finditer("abcd", -1, 1)],
+                             [])
+        self.assertEqual(str(cm.warning), "Negative start index will not "
+                         "be truncated to zero in the future")
+
+        with self.assertWarns(FutureWarning) as cm:
+            self.assertEqual([m[0] for m in pat.finditer("abcd", 1, -1)],
+                             ['b', 'c'])
+        self.assertEqual(str(cm.warning), "Negative end index will not "
+                         "be truncated to zero in the future")
+
+        with self.assertWarns(FutureWarning) as cm:
+            self.assertEqual([m[0] for m in pat.finditer("abcd", 1, 3)],
+                            ['b', 'c'])
+            self.assertEqual([m[0] for m in pat.finditer("abcd", 1, -1)],
+                            ['b', 'c'])
+            self.assertEqual([m[0] for m in pat.finditer("abcd", -3, -1)],
+                            ['b', 'c'])
+            self.assertEqual([m[0] for m in pat.finditer("abcd", -3, 3)],
+                            ['b', 'c'])
+            self.assertEqual([m[0] for m in pat.finditer("abcd", -1, 1)],
+                            [])
+            self.assertEqual([m[0] for m in pat.finditer("abcd", -1, -3)],
+                            [])
+            self.assertEqual([m[0] for m in pat.finditer("abcd", -200, -1)],
+                            ['a', 'b', 'c'])
+            self.assertEqual([m[0] for m in pat.finditer("abcd", -200, -100)],
+                            [])
+            self.assertEqual([m[0] for m in pat.finditer("abcd", pos=1,
+                                                        endpos=-1)], ['b', 'c'])
+        self.assertEqual(len(cm.warnings), 12)
+
     def test_re_match(self):
         for string in 'a', S('a'):
             self.assertEqual(re.match('a', string).groups(), ())
diff --git a/Misc/ACKS b/Misc/ACKS
index 94cb1965676f484..548b26f1786f26e 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -1873,6 +1873,7 @@ Steven Troxler
 Brent Tubbs
 Anthony Tuininga
 Erno Tukia
+Anıl Tuncel
 Adam Turner
 David Turner
 Stephen Turner
diff --git a/Misc/NEWS.d/next/Library/2019-07-13-15-23-34.bpo-7940.NDghRj.rst b/Misc/NEWS.d/next/Library/2019-07-13-15-23-34.bpo-7940.NDghRj.rst
new file mode 100644
index 000000000000000..bad823178b79bdf
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2019-07-13-15-23-34.bpo-7940.NDghRj.rst
@@ -0,0 +1,2 @@
+Add support for negative end positions to re.finditer and re.findall
+(original patch by Matthew Barnett, tests and PR by Mustafa Anıl Tuncel).
diff --git a/Modules/_sre/sre.c b/Modules/_sre/sre.c
index 0f134b194de6f67..fc9143f62ae646a 100644
--- a/Modules/_sre/sre.c
+++ b/Modules/_sre/sre.c
@@ -482,11 +482,23 @@ state_init(SRE_STATE* state, PatternObject* pattern, PyObject* string,
     }
 
     /* adjust boundaries */
+    if (start < 0) {
+        PyErr_WarnEx(PyExc_FutureWarning,
+                     "Negative start index will not be truncated to zero in the future",
+                     1);
+        start += length;
+    }
     if (start < 0)
         start = 0;
     else if (start > length)
         start = length;
 
+    if (end < 0) {
+        PyErr_WarnEx(PyExc_FutureWarning,
+                     "Negative end index will not be truncated to zero in the future",
+                     1);
+        end += length;
+    }
     if (end < 0)
         end = 0;
     else if (end > length)