[PATCH] D11143: [RFC] Cross Block DSE

[Karthik Bhat via llvm-commits]

karthikthecool marked 2 inline comments as done.
karthikthecool added a comment.

Hi Daniel,Hal,
Thanks for the review. Please find my comments inline. I will try to upload the updated patch shortly.
Thanks and Regards
Karthik


================
Comment at: lib/Transforms/Scalar/DeadStoreElimination.cpp:101
@@ +100,3 @@
+      PDT = &getAnalysis<PostDominatorTree>();
+      if (PDT->getRootNode()) {
+        int Count = PDT->getRootNode()->getDFSNumOut();
----------------
dberlin wrote:
> Do you have a testcase for where PDT->getRootNode() is null?
> 
> because that seems broken :)
> 
Hi Daniel,
I found in the below case we were getting getRootNode as NULL so added the above check.
  void foo() {
    while(1);
  }

================
Comment at: lib/Transforms/Scalar/DeadStoreElimination.cpp:108
@@ +107,3 @@
+        // If we have more than 1 block try to populate candidate store.
+        if (Count > 1)
+          populateCandidateStores(F);
----------------
dberlin wrote:
> So, if we only have 1 block, why are you doing the rest of the work here, instead of returning false and exiting?
> :)
> 
Updated code to executed FindFunctionBackedges and BackEdgesMap population only if Count > 1. I think we cannot return false here because we still need to do single block dse.


http://reviews.llvm.org/D11143