From b1f25ac188653afdc35899e4c1d68c59141ba7cf Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Wed, 13 Apr 2005 02:58:13 +0000 Subject: add back the optimization that Nate added for shl X, (zext_inreg y) llvm-svn: 21273 --- llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 25 +++++++++++++++++++++++-- 1 file changed, 23 insertions(+), 2 deletions(-) (limited to 'llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp') diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp index dc862b38bea..48e0f7bc9ad 100644 --- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp @@ -943,8 +943,18 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT, case ISD::SHL: case ISD::SRL: case ISD::SRA: - if (N2.getOpcode() == ISD::SIGN_EXTEND_INREG) + if (N2.getOpcode() == ISD::SIGN_EXTEND_INREG && + cast(N2)->getExtraValueType() != MVT::i1) return getNode(Opcode, VT, N1, N2.getOperand(0)); + else if (N2.getOpcode() == ISD::AND) + if (ConstantSDNode *AndRHS = dyn_cast(N2.getOperand(1))) { + // If the and is only masking out bits that cannot effect the shift, + // eliminate the and. + unsigned NumBits = MVT::getSizeInBits(VT); + if ((AndRHS->getValue() & (NumBits-1)) == NumBits-1) + return getNode(Opcode, VT, N1, N2.getOperand(0)); + } + break; } @@ -1040,8 +1050,19 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT, case ISD::SRA_PARTS: case ISD::SRL_PARTS: case ISD::SHL_PARTS: - if (N3.getOpcode() == ISD::SIGN_EXTEND_INREG) + if (N3.getOpcode() == ISD::SIGN_EXTEND_INREG && + cast(N3)->getExtraValueType() != MVT::i1) return getNode(Opcode, VT, N1, N2, N3.getOperand(0)); + else if (N3.getOpcode() == ISD::AND) + if (ConstantSDNode *AndRHS = dyn_cast(N3.getOperand(1))) { + // If the and is only masking out bits that cannot effect the shift, + // eliminate the and. + unsigned NumBits = MVT::getSizeInBits(VT)*2; + if ((AndRHS->getValue() & (NumBits-1)) == NumBits-1) + return getNode(Opcode, VT, N1, N2, N3.getOperand(0)); + } + + break; } -- cgit v1.2.3