Imported Upstream version 6.0.0.172

Former-commit-id: f3cc9b82f3e5bd8f0fd3ebc098f789556b44e9cd

external/llvm/utils/bisect

@@ -0,0 +1,37 @@
+#!/usr/bin/env python
+
+import os
+import sys
+import argparse
+import subprocess
+
+parser = argparse.ArgumentParser()
+
+parser.add_argument('--start', type=int, default=0)
+parser.add_argument('--end', type=int, default=(1 << 32))
+parser.add_argument('command', nargs='+')
+
+args = parser.parse_args()
+
+start = args.start
+end = args.end
+
+print("Bisect Starting!")
+print("Start: %d" % start)
+print("End: %d" % end)
+
+last = None
+while start != end and start != end-1:
+    count = start + (end - start)/2
+    print("Visiting Count: %d with (Start, End) = (%d,%d)" % (count, start, end))
+    cmd = [x % {'count':count} for x in args.command]
+    print cmd
+    result = subprocess.call(cmd)
+    if result == 0:
+        print("    PASSES! Setting start to count")
+        start = count
+    else:
+        print("    FAILS! Setting end to count")
+        end = count
+
+print("Last good count: %d" % start)