[llvm] [InstCombine] Canonicalize (a + 1 == 0) ? -1 : a + 1 -> uadd.sat(a, 1) (PR #144566)

[via llvm-commits]

AZero13 wrote:

    // Match special-case for increment-by-1.
    if (Pred == ICmpInst::ICMP_EQ) {
      // (a + 1) == 0
      // (1 + a) == 0
      if (AddExpr.match(ICmpLHS) && m_ZeroInt().match(ICmpRHS) &&
          (m_One().match(AddLHS) || m_One().match(AddRHS)))
        return L.match(AddLHS) && R.match(AddRHS) && S.match(ICmpLHS);
      // 0 == (a + 1)
      // 0 == (1 + a)
      if (m_ZeroInt().match(ICmpLHS) && AddExpr.match(ICmpRHS) &&
          (m_One().match(AddLHS) || m_One().match(AddRHS)))
        return L.match(AddLHS) && R.match(AddRHS) && S.match(ICmpRHS);
    }
    
    So does this mean I can remove this from UAddWithOverflow_match?

https://github.com/llvm/llvm-project/pull/144566