[llvm] [InstCombine] move foldAndOrOfICmpsOfAndWithPow2 into foldLogOpOfMaskedICmps (PR #121970)

[Nikita Popov via llvm-commits]

================
@@ -587,93 +588,111 @@ static Value *foldLogOpOfMaskedICmps(ICmpInst *LHS, ICmpInst *RHS, bool IsAnd,
     return Builder.CreateICmp(NewCC, NewAnd2, A);
   }
 
-  // Remaining cases assume at least that B and D are constant, and depend on
-  // their actual values. This isn't strictly necessary, just a "handle the
-  // easy cases for now" decision.
   const APInt *ConstB, *ConstD;
-  if (!match(B, m_APInt(ConstB)) || !match(D, m_APInt(ConstD)))
-    return nullptr;
-
-  if (Mask & (Mask_NotAllZeros | BMask_NotAllOnes)) {
-    // (icmp ne (A & B), 0) & (icmp ne (A & D), 0) and
-    // (icmp ne (A & B), B) & (icmp ne (A & D), D)
-    //     -> (icmp ne (A & B), 0) or (icmp ne (A & D), 0)
-    // Only valid if one of the masks is a superset of the other (check "B&D" is
-    // the same as either B or D).
-    APInt NewMask = *ConstB & *ConstD;
-    if (NewMask == *ConstB)
-      return LHS;
-    else if (NewMask == *ConstD)
-      return RHS;
-  }
-
-  if (Mask & AMask_NotAllOnes) {
-    // (icmp ne (A & B), B) & (icmp ne (A & D), D)
-    //     -> (icmp ne (A & B), A) or (icmp ne (A & D), A)
-    // Only valid if one of the masks is a superset of the other (check "B|D" is
-    // the same as either B or D).
-    APInt NewMask = *ConstB | *ConstD;
-    if (NewMask == *ConstB)
-      return LHS;
-    else if (NewMask == *ConstD)
-      return RHS;
-  }
-
-  if (Mask & (BMask_Mixed | BMask_NotMixed)) {
-    // Mixed:
-    // (icmp eq (A & B), C) & (icmp eq (A & D), E)
-    // We already know that B & C == C && D & E == E.
-    // If we can prove that (B & D) & (C ^ E) == 0, that is, the bits of
-    // C and E, which are shared by both the mask B and the mask D, don't
-    // contradict, then we can transform to
-    // -> (icmp eq (A & (B|D)), (C|E))
-    // Currently, we only handle the case of B, C, D, and E being constant.
-    // We can't simply use C and E because we might actually handle
-    //   (icmp ne (A & B), B) & (icmp eq (A & D), D)
-    // with B and D, having a single bit set.
-
-    // NotMixed:
-    // (icmp ne (A & B), C) & (icmp ne (A & D), E)
-    // -> (icmp ne (A & (B & D)), (C & E))
-    // Check the intersection (B & D) for inequality.
-    // Assume that (B & D) == B || (B & D) == D, i.e B/D is a subset of D/B
-    // and (B & D) & (C ^ E) == 0, bits of C and E, which are shared by both the
-    // B and the D, don't contradict.
-    // Note that we can assume (~B & C) == 0 && (~D & E) == 0, previous
-    // operation should delete these icmps if it hadn't been met.
-
-    const APInt *OldConstC, *OldConstE;
-    if (!match(C, m_APInt(OldConstC)) || !match(E, m_APInt(OldConstE)))
-      return nullptr;
-
-    auto FoldBMixed = [&](ICmpInst::Predicate CC, bool IsNot) -> Value * {
-      CC = IsNot ? CmpInst::getInversePredicate(CC) : CC;
-      const APInt ConstC = PredL != CC ? *ConstB ^ *OldConstC : *OldConstC;
-      const APInt ConstE = PredR != CC ? *ConstD ^ *OldConstE : *OldConstE;
+  if (match(B, m_APInt(ConstB)) && match(D, m_APInt(ConstD))) {
+
----------------
nikic wrote:

nit: Drop empty line.

https://github.com/llvm/llvm-project/pull/121970