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[X86] LowerRotate - recognise hidden ROTR patterns for better vXi8 codegen

Authored by RKSimon on Fri, Nov 19, 3:48 AM.

Description

[X86] LowerRotate - recognise hidden ROTR patterns for better vXi8 codegen

Check for a hidden ISD::ROTR (rotl(sub(0,x))) - vXi8 lowering can handle both (its always beneficial for splats, but otherwise only if we have VPTERNLOG).

We currently hit infinite loops in TargetLowering::expandROT if we set ISD::ROTR to custom, which needs addressing before we extend this much further.

Details

Committed
RKSimonFri, Nov 19, 3:49 AM
Parents
rG47eb3f155f9e: [ELF] Ensure output section is not discarded in addStartEndSymbols()
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