[PATCH] D152116: [DAGCombiner] Transform `(icmp eq/ne (and X,C0),(shift X,C1))` to use rotate or to getter constants.

[Noah Goldstein via Phabricator via llvm-commits]

goldstein.w.n marked 2 inline comments as done.
goldstein.w.n added inline comments.


================
Comment at: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:12496
+            IsRotate ||
+            (*ShiftCAmt == (~*AndCMask).popcount() && ShiftOpc == ISD::SHL
+                 ? (~*AndCMask).isMask()
----------------
RKSimon wrote:
> (~*AndCMask).popcount() - is this the same as !AndCMask->isAllOnes() ?
No, we are checking for something like:
`(icmp eq  (and X, 0x1f), (srl, X, 3)`. Not all ones.


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  https://reviews.llvm.org/D152116/new/

https://reviews.llvm.org/D152116