[PATCH] D118012: [DAGCombiner][RISCV] Canonicalize (bswap(bitreverse(x))->bitreverse(bswap(x)).

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon accepted this revision.
RKSimon added a comment.
This revision is now accepted and ready to land.

LGTM - cheers



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Comment at: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:9380
+  // Canonicalize bswap(bitreverse(x)) -> bitreverse(bswap(x)). This helps
+  // when bitreverse gets expanded.
+  if (N0.getOpcode() == ISD::BITREVERSE && N0.hasOneUse()) {
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Maybe mention its because expandBITREVERSE tries to perform a bswap first?


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  https://reviews.llvm.org/D118012/new/

https://reviews.llvm.org/D118012