diff -r 11cf18ec1900 Lib/sre_compile.py
--- a/Lib/sre_compile.py	Sat Sep 06 22:49:07 2014 +0300
+++ b/Lib/sre_compile.py	Mon Sep 08 22:53:42 2014 +0300
@@ -53,7 +53,7 @@
                     return _sre.getlower(literal, flags)
             else:
                 emit(OPCODES[op])
-                fixup = _identityfunction
+                fixup = None
             skip = _len(code); emit(0)
             _compile_charset(av, flags, code, fixup)
             code[skip] = _len(code) - skip
@@ -172,17 +172,15 @@
 def _compile_charset(charset, flags, code, fixup=None):
     # compile charset subprogram
     emit = code.append
-    if fixup is None:
-        fixup = _identityfunction
     for op, av in _optimize_charset(charset, fixup):
         emit(OPCODES[op])
         if op is NEGATE:
             pass
         elif op is LITERAL:
-            emit(fixup(av))
+            emit(av)
         elif op is RANGE:
-            emit(fixup(av[0]))
-            emit(fixup(av[1]))
+            emit(av[0])
+            emit(av[1])
         elif op is CHARSET:
             code.extend(av)
         elif op is BIGCHARSET:
@@ -207,9 +205,15 @@
         while True:
             try:
                 if op is LITERAL:
-                    charmap[fixup(av)] = 1
+                    i = av
+                    if fixup is not None:
+                        i = fixup(i)
+                    charmap[i] = 1
                 elif op is RANGE:
-                    for i in range(fixup(av[0]), fixup(av[1])+1):
+                    r = range(av[0], av[1]+1)
+                    if fixup is not None:
+                        r = map(fixup, r)
+                    for i in r:
                         charmap[i] = 1
                 elif op is NEGATE:
                     out.append((op, av))
@@ -221,7 +225,27 @@
                     charmap += b'\0' * 0xff00
                     continue
                 # character set contains non-BMP character codes
-                tail.append((op, av))
+                if fixup is None or op is not RANGE:
+                    tail.append((op, av))
+                else:
+                    hi = -2
+                    for i in map(fixup, range(av[0], av[1]+1)):
+                        if i == hi + 1:
+                            hi = i
+                        elif i < 0x10000:
+                            charmap[i] = 1
+                        else:
+                            if hi >= 0:
+                                if lo == hi:
+                                    tail.append((LITERAL, hi))
+                                else:
+                                    tail.append((RANGE, (lo, hi)))
+                            lo = hi = i
+                    if hi >= 0:
+                        if lo == hi:
+                            tail.append((LITERAL, hi))
+                        else:
+                            tail.append((RANGE, (lo, hi)))
             break
 
     # compress character map
@@ -247,7 +271,7 @@
             else:
                 out.append((RANGE, (p, q - 1)))
         out += tail
-        if len(out) < len(charset):
+        if fixup is not None or len(out) < len(charset):
             return out
         return charset
 
diff -r 11cf18ec1900 Lib/test/test_re.py
--- a/Lib/test/test_re.py	Sat Sep 06 22:49:07 2014 +0300
+++ b/Lib/test/test_re.py	Mon Sep 08 22:53:42 2014 +0300
@@ -577,6 +577,25 @@
         self.assertEqual(re.match(r"((a)\s(abc|a))", "a a", re.I).group(1), "a a")
         self.assertEqual(re.match(r"((a)\s(abc|a)*)", "a aa", re.I).group(1), "a aa")
 
+    def test_ignore_case_range(self):
+        # Issues #3511, #17381.
+        self.assertIsNone(re.match(r'[9-A]', '_', re.I))
+        self.assertIsNone(re.match(br'[9-A]', b'_', re.I))
+        self.assertIsNotNone(re.match(r'[\xc0-\xde]', '\xd7', re.I))
+        self.assertIsNone(re.match(r'[\xc0-\xde]', '\xf7', re.I))
+        self.assertIsNotNone(re.match(r'[\u0430-\u045f]', '\u0450', re.I))
+        self.assertIsNotNone(re.match(r'[\u0430-\u045f]', '\u0400', re.I))
+        self.assertIsNotNone(re.match(r'[\u0400-\u042f]', '\u0450', re.I))
+        self.assertIsNotNone(re.match(r'[\u0400-\u042f]', '\u0400', re.I))
+        self.assertIsNotNone(
+            re.match(r'[\U00010428-\U0001044f]', '\U00010428', re.I))
+        self.assertIsNotNone(
+            re.match(r'[\U00010428-\U0001044f]', '\U00010400', re.I))
+        self.assertIsNotNone(
+            re.match(r'[\U00010400-\U00010427]', '\U00010428', re.I))
+        self.assertIsNotNone(
+            re.match(r'[\U00010400-\U00010427]', '\U00010400', re.I))
+
     def test_category(self):
         self.assertEqual(re.match(r"(\s)", " ").group(1), " ")