[PATCH] D96440: [knownbits] Preserve known bits for small shift recurrences

[Nikita Popov via Phabricator via llvm-commits]

nikic added inline comments.


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Comment at: llvm/lib/Analysis/ValueTracking.cpp:1343
+    // An ashr recurrence will extend the initial sign bit
+    RefineRecurrence(I, DemandedElts, Known, Known2, Depth, Q);
     break;
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Why do we need to do this both starting from the shifts and starting from the phi? The existing code for add recurrences only starts from phis.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D96440/new/

https://reviews.llvm.org/D96440