[PATCH] D112443: [SelectionDAG] Optimize expansion for rotates/funnel shifts

[Craig Topper via Phabricator via llvm-commits]

craig.topper added inline comments.


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Comment at: llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp:4427
+  // Expand to a pair of funnel shifts.
+  EVT NewShAmtVT = TLI.getShiftAmountTy(HalfVT, DAG.getDataLayout(), false);
+  SDValue NewShAmt = DAG.getAnyExtOrTrunc(ShAmt, DL, NewShAmtVT);
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Does passing "false" to this really solve the original problem I raised? That makes getShiftAmountTy use pointer type, but pointer type on some targets is i16 which wouldn't be enough to represent a shift amount for an i65356. Should this instead use the getShiftAmountTyForConstant helper? The name of that function is outdated.


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  https://reviews.llvm.org/D112443/new/

https://reviews.llvm.org/D112443