[PATCH] Teach ScalarEvolution to sharpen range information.

[Sanjoy Das]

================
Comment at: lib/Analysis/ScalarEvolution.cpp:6541
@@ +6540,3 @@
+      if (Min!= CI->getValue()) return false; // nothing to sharpen
+      Min++;
+
----------------
This line is incorrect -- below in the `switch` I've assumed that `Min` is the unsharpened minimum value.

http://reviews.llvm.org/D5639