Index: test/FileCheck/repeat-in-regex.txt
===================================================================
--- /dev/null
+++ test/FileCheck/repeat-in-regex.txt
@@ -0,0 +1,13 @@
+// RUN: FileCheck -input-file %s %s
+
+text to be matchedmatchedmatchedmatchedmatched
+// CHECK: {{(matched){5}}}
+
+r1, is register is register is register is register is register
+// CHECK: [[REG:r[0-9]{1,2}]]
+// CHECK-SAME: {{(is register ){1,}}}
+
+r2r13r1
+dag
+// CHECK-DAG: {{dag{1}}}
+// CHECK-DAG: {{[[REG]]{,2}}}
Index: utils/FileCheck/FileCheck.cpp
===================================================================
--- utils/FileCheck/FileCheck.cpp
+++ utils/FileCheck/FileCheck.cpp
@@ -237,14 +237,31 @@
         return true;
       }
 
+      size_t NextChar = End + 2;
+      while (NextChar < PatternStr.size() && PatternStr[NextChar] == '}') {
+        NextChar++;
+      }
+
+      End = NextChar - 2;
+
       // Enclose {{}} patterns in parens just like [[]] even though we're not
       // capturing the result for any purpose.  This is required in case the
       // expression contains an alternation like: CHECK:  abc{{x|z}}def.  We
       // want this to turn into: "abc(x|z)def" not "abcx|zdef".
       RegExStr += '(';
       ++CurParen;
+      
+      StringRef RegexPart = PatternStr.substr(2, End-2);
+      // Find quantifier for replacing.
+      size_t NullQuantifier = RegexPart.find("{,");
+      if (NullQuantifier != StringRef::npos && (NullQuantifier == 0 || RegexPart[NullQuantifier - 1] != '\\')) {
+        // Need replacing.
+        StringRef FirstPart = RegexPart.drop_back(RegexPart.size() - NullQuantifier - 1);
+        StringRef SecondPart = RegexPart.drop_front(NullQuantifier + 1);
+        RegexPart = StringRef(FirstPart.str() + "0" + SecondPart.str());
+      }
 
-      if (AddRegExToRegEx(PatternStr.substr(2, End-2), CurParen, SM))
+      if (AddRegExToRegEx(RegexPart, CurParen, SM))
         return true;
       RegExStr += ')';