diff --git a/mercurial/util.py b/mercurial/util.py
--- a/mercurial/util.py
+++ b/mercurial/util.py
@@ -1996,7 +1996,7 @@ def matchdate(date):
         start, stop = lower(date), upper(date)
         return lambda x: x >= start and x <= stop
 
-def stringmatcher(pattern):
+def stringmatcher(pattern, casesensitive=True):
     """
     accepts a string, possibly starting with 're:' or 'literal:' prefix.
     returns the matcher name, pattern, and matcher function.
@@ -2006,6 +2006,9 @@ def stringmatcher(pattern):
     >>> def test(pattern, *tests):
     ...     kind, pattern, matcher = stringmatcher(pattern)
     ...     return (kind, pattern, [bool(matcher(t)) for t in tests])
+    >>> def itest(pattern, *tests):
+    ...     kind, pattern, matcher = stringmatcher(pattern, casesensitive=False)
+    ...     return (kind, pattern, [bool(matcher(t)) for t in tests])
 
     exact matching (no prefix):
     >>> test('abcdefg', 'abc', 'def', 'abcdefg')
@@ -2022,18 +2025,35 @@ def stringmatcher(pattern):
     unknown prefixes are ignored and treated as literals
     >>> test('foo:bar', 'foo', 'bar', 'foo:bar')
     ('literal', 'foo:bar', [False, False, True])
+
+    case insensitive regex matches
+    >>> itest('re:A.+b', 'nomatch', 'fooadef', 'fooadefBar')
+    ('re', 'A.+b', [False, False, True])
+
+    case insensitive literal matches
+    >>> itest('ABCDEFG', 'abc', 'def', 'abcdefg')
+    ('literal', 'ABCDEFG', [False, False, True])
     """
     if pattern.startswith('re:'):
         pattern = pattern[3:]
         try:
-            regex = remod.compile(pattern)
+            flags = 0
+            if not casesensitive:
+                flags = remod.I
+            regex = remod.compile(pattern, flags)
         except remod.error as e:
             raise error.ParseError(_('invalid regular expression: %s')
                                    % e)
         return 're', pattern, regex.search
     elif pattern.startswith('literal:'):
         pattern = pattern[8:]
-    return 'literal', pattern, pattern.__eq__
+
+    match = pattern.__eq__
+
+    if not casesensitive:
+        ipat = encoding.lower(pattern)
+        match = lambda s: ipat == encoding.lower(s)
+    return 'literal', pattern, match
 
 def shortuser(user):
     """Return a short representation of a user name or email address."""