[llvm-commits] Patch resubmit: ROTL/ROTR cleanups

[Scott Michel]

On Apr 2, 2007, at 1:11 PM, Chris Lattner wrote:

> On Mar 30, 2007, at 12:02 PM, Scott Michel wrote:
>> Spotted what was probably a long-standing bug, since some of my  
>> cleanups
>> were simple substitutions.
>
> Sorry for the delay.  In general, if you keep the changes as simple  
> and disjoint as possible, I'm more likely to look at them soon :).   
> Here you could split up the "allow custom legalize of rotates" part  
> from the "introduce some temporary vars" part from "match ext  
> rotate cases" part.

I did, I did, I did! Really! They're part and parcel of the same  
functionality... :-)

>> +
>> +  // Look for sign/zext/any-extended cases:
>> +  if ((LHSShiftAmt.getOpcode() == ISD::SIGN_EXTEND
>> +       || LHSShiftAmt.getOpcode() == ISD::ZERO_EXTEND
>> +       || LHSShiftAmt.getOpcode() == ISD::ANY_EXTEND) &&
>> +      (RHSShiftAmt.getOpcode() == ISD::SIGN_EXTEND
>> +       || RHSShiftAmt.getOpcode() == ISD::ZERO_EXTEND
>> +       || RHSShiftAmt.getOpcode() == ISD::ANY_EXTEND)) {
>> +    SDOperand LExtOp0 = LHSShiftAmt.getOperand(0);
>> +    SDOperand RExtOp0 = RHSShiftAmt.getOperand(0);
>> +    if (RExtOp0.getOpcode() == ISD::SUB &&
>> +        RExtOp0.getOperand(1) == LExtOp0) {
>> +      // fold (or (shl x, (*ext y)), (srl x, (*ext (sub 32, y)))) ->
>> +      //   (rotr x, y)
>> +      // fold (or (shl x, (*ext y)), (srl x, (*ext (sub 32, y)))) ->
>> +      //   (rotl x, (sub 32, y))
>> +      if (ConstantSDNode *SUBC = cast<ConstantSDNode> 
>> (RExtOp0.getOperand(0))) {
>> +	if (SUBC->getValue() == OpSizeInBits) {
>> +	  if (HasROTL)
>> +	    return DAG.getNode(ISD::ROTL, VT, LHSShiftArg,  
>> LHSShiftAmt).Val;
>> +	  else
>> +	    return DAG.getNode(ISD::ROTR, VT, LHSShiftArg,  
>> RHSShiftAmt).Val;
>> +	}
>
> Okay, but needs an extra level of spacing for the indentation here  
> (2 spaces, not 1).
>
>> +      }
>> +    } else if (LExtOp0.getOpcode() == ISD::SUB &&
>> +               RExtOp0 == LExtOp0.getOperand(1)) {
>> +      // fold (or (shl x, (*ext (sub 32, y))), (srl x, (*ext r))) ->
>> +      //   (rotl x, y)
>> +      // fold (or (shl x, (*ext (sub 32, y))), (srl x, (*ext r))) ->
>> +      //   (rotr x, (sub 32, y))
>> +      if (ConstantSDNode *SUBC = cast<ConstantSDNode> 
>> (LExtOp0.getOperand(0))) {
>> +	if (SUBC->getValue() == OpSizeInBits) {
>> +	  if (HasROTL)
>> +	    return DAG.getNode(ISD::ROTL, VT, LHSShiftArg,  
>> RHSShiftAmt).Val;
>> +	  else
>> +	    return DAG.getNode(ISD::ROTL, VT, LHSShiftArg,  
>> LHSShiftAmt).Val;
>> +	}
>
> Likewise.

Fixed tab violations, which made it look like incorrect indentation...


-scooter