[PATCH] [GVN] Perform Scalar PRE on gep indices that feed loads before doing Load PRE

[Balaram Makam]

================
Comment at: lib/Transforms/Scalar/GVN.cpp:2655
@@ -2639,3 +2654,3 @@
   bool Changed = false;
-#if 0
+#if 1
   // Needed for value numbering with phi construction to work.
----------------
hfinkel wrote:
> If the patch turns this on, please just remove the #if.
I will turn on the slow path and turn off the fast path in my next patch that I will upload with full context. I am  not sure if we still want to keep the fast path commented out in the code or clean it up.

http://reviews.llvm.org/D6103