[PATCH] When canonicalizing gep indices, prefer zext when possible (SelectionDAGBuilder)

hfinkel at anl.gov hfinkel at anl.gov
Fri Feb 13 15:52:51 PST 2015


Part of the issue is that this canonicalization already exists in DAGCombine (at the end of DAGCombiner::visitSIGN_EXTEND):

  // fold (sext x) -> (zext x) if the sign bit is known zero.
  if ((!LegalOperations || TLI.isOperationLegal(ISD::ZERO_EXTEND, VT)) &&
      DAG.SignBitIsZero(N0))
    return DAG.getNode(ISD::ZERO_EXTEND, SDLoc(N), VT, N0);

As a result, I'm not sure this is needed.


http://reviews.llvm.org/D7626

EMAIL PREFERENCES
  http://reviews.llvm.org/settings/panel/emailpreferences/






More information about the llvm-commits mailing list