[all-commits] [llvm/llvm-project] 481b18: [X86] combineCarryThroughADD - recognise X86ISD::A...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 481b18562077d93be3d6f24586445034c19277d6
      https://github.com/llvm/llvm-project/commit/481b18562077d93be3d6f24586445034c19277d6
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2022-03-31 (Thu, 31 Mar 2022)

  Changed paths:
    M llvm/lib/Target/X86/X86ISelLowering.cpp
    M llvm/test/CodeGen/X86/addcarry.ll
    M llvm/test/CodeGen/X86/combine-adc.ll
    M llvm/test/CodeGen/X86/subcarry.ll

  Log Message:
  -----------
  [X86] combineCarryThroughADD - recognise X86ISD::ADD(AND(X,1),-1) pattern can be folded to X86ISD::BT

As mentioned on D122482, if we've generated a masked overflow test see if we can fold it to X86ISD::BT to feed a X86ISD::ADC/SBB

Differential Revision: https://reviews.llvm.org/D122572