[PATCH] D125301: [LoopVectorize] Add option to use active lane mask for loop control flow

[Florian Hahn via Phabricator via llvm-commits]

fhahn added inline comments.


================
Comment at: llvm/lib/Transforms/Vectorize/VPlan.cpp:1552
+                        &*State.CFG.PrevBB->getFirstInsertionPt());
+    EntryPart->addIncoming(StartMask, VectorPH);
+    EntryPart->setDebugLoc(DL);
----------------
david-arm wrote:
> Hi @fhahn, if I use VPWidenPHIRecipe instead it's not obvious how I add the incoming start mask. It looks like VPWidenPHIRecipe::execute doesn't add it - do you know how?
I think D128937 should do the trick, together with the snippet below. If D128937 allows `VPWidenPHIRecipe` to be used here I'll send it for review.

```
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index d8fb7a9c12b0..1ba76bf52cc6 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -3646,8 +3646,7 @@ void InnerLoopVectorizer::fixVectorizedLoop(VPTransformState &State,
     truncateToMinimalBitwidths(State);

   // Fix widened non-induction PHIs by setting up the PHI operands.
-  if (EnableVPlanNativePath)
-    fixNonInductionPHIs(Plan, State);
+  fixNonInductionPHIs(Plan, State);

   // At this point every instruction in the original loop is widened to a
   // vector form. Now we need to fix the recurrences in the loop. These PHI
```


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D125301/new/

https://reviews.llvm.org/D125301