[PATCH] D104079: [RISCV] Use ComputeNumSignBits/MaskedValueIsZero in RISCVDAGToDAGISel::selectSExti32/selectZExti32.

[Jessica Clarke via Phabricator via llvm-commits]

jrtc27 added inline comments.


================
Comment at: llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp:1341
   }
-  // FIXME: Should we just call computeNumSignBits here?
-  if (N.getOpcode() == ISD::AssertSext &&
----------------
Narrator: yes, yes they should :)


================
Comment at: llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp:1352-1356
     auto *C = dyn_cast<ConstantSDNode>(N.getOperand(1));
     if (C && C->getZExtValue() == UINT64_C(0xFFFFFFFF)) {
       Val = N.getOperand(0);
       return true;
     }
----------------
You could generalise this with computeKnownBits. I don't know if that is a useful thing to do or not though.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D104079/new/

https://reviews.llvm.org/D104079