[DAGCombiner] Simplify foldAndOrOfSETCC. NFC.

[foad]

Summary

Pull out repeated hasOneUse checks. Simplify some conditions. Reduce
indentation.

[kmitropoulou]

LGTM! Thank you :)

llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

static SDValue foldAndOrOfSETCC(SDNode *LogicOp, SelectionDAG &DAG) {
   using AndOrSETCCFoldKind = TargetLowering::AndOrSETCCFoldKind;
   assert(
       (LogicOp->getOpcode() == ISD::AND || LogicOp->getOpcode() == ISD::OR) &&
       "Invalid Op to combine SETCC with");
 
   // TODO: Search past casts/truncates.
   SDValue LHS = LogicOp->getOperand(0);
   SDValue RHS = LogicOp->getOperand(1);
-  if (LHS->getOpcode() != ISD::SETCC || RHS->getOpcode() != ISD::SETCC)
+  if (LHS->getOpcode() != ISD::SETCC || RHS->getOpcode() != ISD::SETCC ||
+      !LHS->hasOneUse() || !RHS->hasOneUse())
     return SDValue();
 
   const TargetLowering &TLI = DAG.getTargetLoweringInfo();
   AndOrSETCCFoldKind TargetPreference = TLI.isDesirableToCombineLogicOpOfSETCC(
       LogicOp, LHS.getNode(), RHS.getNode());
 
   SDValue LHS0 = LHS->getOperand(0);
   SDValue RHS0 = RHS->getOperand(0);
static SDValue foldAndOrOfSETCC(SDNode *LogicOp, SelectionDAG &DAG) {
 
   // Check if the operands of an and/or operation are comparisons and if they
   // compare against the same value. Replace the and/or-cmp-cmp sequence with
   // min/max cmp sequence. If LHS1 is equal to RHS1, then the or-cmp-cmp
   // sequence will be replaced with min-cmp sequence:
   // (LHS0 < LHS1) | (RHS0 < RHS1) -> min(LHS0, RHS0) < LHS1
   // and and-cmp-cmp will be replaced with max-cmp sequence:
   // (LHS0 < LHS1) & (RHS0 < RHS1) -> max(LHS0, RHS0) < LHS1
-  if (OpVT.isInteger() && TLI.isOperationLegal(ISD::UMAX, OpVT) &&
-      TLI.isOperationLegal(ISD::SMAX, OpVT) &&
-      TLI.isOperationLegal(ISD::UMIN, OpVT) &&
-      TLI.isOperationLegal(ISD::SMIN, OpVT)) {
-    if (LHS->getOpcode() == ISD::SETCC && RHS->getOpcode() == ISD::SETCC &&
-        LHS->hasOneUse() && RHS->hasOneUse() &&
-        // The two comparisons should have either the same predicate or the
-        // predicate of one of the comparisons is the opposite of the other one.
-        (CCL == CCR || CCL == ISD::getSetCCSwappedOperands(CCR)) &&
-        // The optimization does not work for `==` or `!=` .
-        !ISD::isIntEqualitySetCC(CCL) && !ISD::isIntEqualitySetCC(CCR)) {
-      SDValue CommonValue, Operand1, Operand2;
-      ISD::CondCode CC = ISD::SETCC_INVALID;
-      if (CCL == CCR) {
-        if (LHS0 == RHS0) {
-          CommonValue = LHS0;
-          Operand1 = LHS1;
-          Operand2 = RHS1;
-          CC = ISD::getSetCCSwappedOperands(CCL);
-        } else if (LHS1 == RHS1) {
-          CommonValue = LHS1;
-          Operand1 = LHS0;
-          Operand2 = RHS0;
-          CC = CCL;
-        }
-      } else {
-        assert(CCL == ISD::getSetCCSwappedOperands(CCR) && "Unexpected CC");
-        if (LHS0 == RHS1) {
-          CommonValue = LHS0;
-          Operand1 = LHS1;
-          Operand2 = RHS0;
-          CC = ISD::getSetCCSwappedOperands(CCL);
-        } else if (RHS0 == LHS1) {
-          CommonValue = LHS1;
-          Operand1 = LHS0;
-          Operand2 = RHS1;
-          CC = CCL;
-        }
-      }
+  // The optimization does not work for `==` or `!=` .
+  if (OpVT.isInteger() && !ISD::isIntEqualitySetCC(CCL) &&
+      TLI.isOperationLegal(ISD::UMAX, OpVT) &&
+      TLI.isOperationLegal(ISD::SMAX, OpVT) &&
+      TLI.isOperationLegal(ISD::UMIN, OpVT) &&
+      TLI.isOperationLegal(ISD::SMIN, OpVT)) {
+        CC = CCR;
 
-      if (CC != ISD::SETCC_INVALID) {
-        unsigned NewOpcode;
-        bool IsSigned = isSignedIntSetCC(CC);
-        if (((CC == ISD::SETLE || CC == ISD::SETULE || CC == ISD::SETLT ||
-              CC == ISD::SETULT) &&
-             (LogicOp->getOpcode() == ISD::OR)) ||
-            ((CC == ISD::SETGE || CC == ISD::SETUGE || CC == ISD::SETGT ||
-              CC == ISD::SETUGT) &&
-             (LogicOp->getOpcode() == ISD::AND)))
-          NewOpcode = IsSigned ? ISD::SMIN : ISD::UMIN;
-        else
-          NewOpcode = IsSigned ? ISD::SMAX : ISD::UMAX;
+      bool IsLess = (CC == ISD::SETLE || CC == ISD::SETULE ||
+                     CC == ISD::SETLT || CC == ISD::SETULT);
+      bool IsOr = (LogicOp->getOpcode() == ISD::OR);
+      if (IsLess == IsOr)
 
-        SDValue MinMaxValue =
-            DAG.getNode(NewOpcode, DL, OpVT, Operand1, Operand2);
-        return DAG.getSetCC(DL, VT, MinMaxValue, CommonValue, CC);
-      }
-    }
-  }
 
   if (TargetPreference == AndOrSETCCFoldKind::None)
     return SDValue();
 
   if (CCL == CCR &&
       CCL == (LogicOp->getOpcode() == ISD::AND ? ISD::SETNE : ISD::SETEQ) &&
-      LHS0 == RHS0 && LHS1C && RHS1C && OpVT.isInteger() && LHS.hasOneUse() &&
-      RHS.hasOneUse()) {
+      LHS0 == RHS0 && LHS1C && RHS1C && OpVT.isInteger()) {
     const APInt &APLhs = LHS1C->getAPIntValue();
     const APInt &APRhs = RHS1C->getAPIntValue();
 
     // Preference is to use ISD::ABS or we already have an ISD::ABS (in which
     // case this is just a compare).
     if (APLhs == (-APRhs) &&
         ((TargetPreference & AndOrSETCCFoldKind::ABS) ||
          DAG.doesNodeExist(ISD::ABS, DAG.getVTList(OpVT), {LHS0}))) {