[PATCH] D122915: [AArch64] Fold lsr+bfi in tryBitfieldInsertOpFromOr

[Eli Friedman via Phabricator via llvm-commits]

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

Yes, this is my "solution 1".  "Solution 2" would be defining AArch64ISD::BFM, and moving all the code from tryBitfieldInsertOpFromOr into a DAGCombine.  The advantage of that is that we can perform general DAGCombine optimizations afterwards, not just this specific one.  The disadvantage is that you have to be careful not to block other optimizations. (And it's more work to modify the current code.)

@benshi001 any further thoughts?


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