Index: clang/utils/creduce-clang-crash.py
===================================================================
--- clang/utils/creduce-clang-crash.py
+++ clang/utils/creduce-clang-crash.py
@@ -23,7 +23,6 @@
 verbose = False
 creduce_cmd = None
 clang_cmd = None
-not_cmd = None
 
 def verbose_print(*args, **kwargs):
   if verbose:
@@ -178,8 +177,8 @@
 
     crash_flag = "--crash" if self.is_crash else ""
 
-    output = "#!/bin/bash\n%s %s %s >& t.log || exit 1\n" % \
-        (pipes.quote(not_cmd), crash_flag, quote_cmd(self.get_crash_cmd()))
+    output = "#!/bin/bash\n! %s %s >& t.log || exit 1\n" % \
+        (crash_flag, quote_cmd(self.get_crash_cmd()))
 
     for msg in self.expected_output:
       output += 'grep %s t.log || exit 1\n' % pipes.quote(msg)
@@ -360,7 +359,6 @@
   global verbose
   global creduce_cmd
   global clang_cmd
-  global not_cmd
 
   parser = ArgumentParser(description=__doc__,
                           formatter_class=RawTextHelpFormatter)
@@ -370,9 +368,6 @@
                       help="Name of the file to be reduced.")
   parser.add_argument('--llvm-bin', dest='llvm_bin', type=str,
                       help="Path to the LLVM bin directory.")
-  parser.add_argument('--llvm-not', dest='llvm_not', type=str,
-                      help="The path to the `not` executable. "
-                      "By default uses the llvm-bin directory.")
   parser.add_argument('--clang', dest='clang', type=str,
                       help="The path to the `clang` executable. "
                       "By default uses the llvm-bin directory.")
@@ -386,7 +381,6 @@
   llvm_bin = os.path.abspath(args.llvm_bin) if args.llvm_bin else None
   creduce_cmd = check_cmd('creduce', None, args.creduce)
   clang_cmd = check_cmd('clang', llvm_bin, args.clang)
-  not_cmd = check_cmd('not', llvm_bin, args.llvm_not)
 
   crash_script = check_file(args.crash_script[0])
   file_to_reduce = check_file(args.file_to_reduce[0])