[PATCH] D127392: [AggressiveInstCombine] Combine consecutive loads which are being merged to form a wider load.

[Sanjay Patel via Phabricator via llvm-commits]

spatel added inline comments.


================
Comment at: llvm/lib/Transforms/AggressiveInstCombine/AggressiveInstCombine.cpp:694-697
+  // Swap loads if LI1 comes later as we handle only forward loads.
+  // This is done as InstCombine folds lowest node forward loads to reverse.
+  // The implementation will be subsequently extended to handle all reverse
+  // loads.
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I didn't notice this limitation before. "Forward" and "reverse" are referring to the order that the `or` instructions use the loaded values?

I agree that we don't want to complicate the initial implementation any more than necessary, but it might help to see how the backend handles that in DAGCombiner::MatchLoadCombine() (see D133584 for a proposed enhancement to that code).


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  https://reviews.llvm.org/D127392/new/

https://reviews.llvm.org/D127392