Please review: Optimize vector multiply on X86

[Demikhovsky, Elena]

I check it before, I can add assert

    ConstantSDNode *N0C = 0;
    ConstantSDNode *N1C = 0;
    if (isSplatVector(LHS.getNode()))
      N0C = dyn_cast<ConstantSDNode>(LHS.getOperand(0).getNode());
    if (isSplatVector(RHS.getNode()))
      N1C = dyn_cast<ConstantSDNode>(RHS.getOperand(0).getNode());

    if (!N0C && !N1C)
      return SDValue();                                   <<= I guarantee that one operand  is constant

    // Canonicalize constant to RHS.
    SDValue N0 = LHS;
    SDValue N1 = RHS;
    if (N0C && !N1C) {
      N0 = RHS;
      N1 = LHS;                                            <<=  I put constant side to N1
    }
    // fold (mul x, 0) -> 0
    if (ISD::isBuildVectorAllZeros(N1.getNode()))
      return N1;

    // fold (mul x, -1) -> 0-x
    if (ISD::isBuildVectorAllOnes(N1.getNode()))
      return DAG.getNode(ISD::SUB, SDLoc(N), VT, DAG.getConstant(0, VT), N0);

    N1C = dyn_cast<ConstantSDNode>(N1.getOperand(0));           <<= at this point I know that N1 is constant, I can add assert

-  Elena

-----Original Message-----
From: Jakub Staszak [mailto:kubastaszak at gmail.com] 
Sent: Sunday, June 16, 2013 15:46
To: Demikhovsky, Elena
Cc: Jakub Staszak; llvm-commits at cs.uiuc.edu
Subject: Re: Please review: Optimize vector multiply on X86

Hi,

You should check whether N1C isn't NULL here:

+    N1C = dyn_cast<ConstantSDNode>(N1.getOperand(0));
+    // fold (mul x, 1) -> x
+    if (N1C->getAPIntValue() == 1)


Best,
Kuba

On Jun 16, 2013, at 2:22 PM, "Demikhovsky, Elena" <elena.demikhovsky at intel.com> wrote:

> <mul.diff>

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