Reapply 122341 to fix PR8199 now that clang changes are in.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122754 91177308-0d34-0410-b5e6-96231b3b80d8

utils/lit/lit/TestRunner.py

@@ -8,6 +8,8 @@ import Util
 import platform
 import tempfile
 
+import re
+
 class InternalShellError(Exception):
     def __init__(self, command, message):
         self.command = command
@@ -444,11 +446,13 @@ def parseIntegratedTestScript(test, normalize_slashes=False):
             if ln[ln.index('END.'):].strip() == 'END.':
                 break
 
-    # Apply substitutions to the script.
+    # Apply substitutions to the script.  Allow full regular
+    # expression syntax.  Replace each matching occurrence of regular
+    # expression pattern a with substitution b in line ln.
     def processLine(ln):
         # Apply substitutions
         for a,b in substitutions:
-            ln = ln.replace(a,b)
+            ln = re.sub(a, b, ln)
 
         # Strip the trailing newline and any extra whitespace.
         return ln.strip()