[PATCH] D88225: [DAG] Fold vector mul(x,0)/mul(x,1) to a clearing mask

[Jay Foad via Phabricator via llvm-commits]

foad added a comment.

Looks good to me but I guess it needs approval from the affected target maintainers.



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Comment at: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:3711
+  if (VT.isFixedLengthVector()) {
+    SmallBitVector ClearMask;
+    auto IsClearMask = [&ClearMask](ConstantSDNode *V) {
----------------
Maybe reserve() space in ClearMask, or initialize it with an explicit length, for efficiency?


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  https://reviews.llvm.org/D88225/new/

https://reviews.llvm.org/D88225