[llvm] [DAGCombiner] Add pattern matching for negated subtraction in ABDU selection (PR #156217)

[Simon Pilgrim via llvm-commits]

https://github.com/RKSimon commented:

Failed Tests (5):
  LLVM :: CodeGen/AArch64/abds-neg.ll
  LLVM :: CodeGen/AArch64/abdu-neg.ll
  LLVM :: CodeGen/RISCV/abds-neg.ll
  LLVM :: CodeGen/RISCV/abdu-neg.ll
  LLVM :: CodeGen/X86/abds-neg.ll


https://github.com/llvm/llvm-project/pull/156217