[X86] X86TargetLowering::SimplifyDemandedBitsForTargetNode - add handling for VPMADD52L/VPMADD52H nodes

[RKSimon]

The X86ISD::VPMADD52L/VPMADD52H nodes only demand the lower 52-bits of operands 0 / 1 (and all 64-bits of operand 2).

Pulled out of #153787

[llvmbot]

@llvm/issue-subscribers-backend-x86

Author: Simon Pilgrim (RKSimon)

The X86ISD::VPMADD52L/VPMADD52H nodes only demand the lower 52-bits of operands 0 / 1 (and all 64-bits of operand 3).

[llvmbot]

Hi!

This issue may be a good introductory issue for people new to working on LLVM. If you would like to work on this issue, your first steps are:

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[llvmbot]

@llvm/issue-subscribers-good-first-issue

Author: Simon Pilgrim (RKSimon)

The X86ISD::VPMADD52L/VPMADD52H nodes only demand the lower 52-bits of operands 0 / 1 (and all 64-bits of operand 3).

[XChy]

only demand the lower 52-bits of operands 0 / 1 (and all 64-bits of operand 3).

operand 3 -> operand 2?