[InstCombine] Use SimplifyQuery in isKnownSign()

This enabled the use of DomConditionCache. As such, remove the
explicit isImpliedByDomCondition() call. This is probably not
entirely NFC because these APIs don't support exactly the same
cases.

Author: nikic

llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp

@@ -1041,45 +1041,39 @@ Instruction *InstCombinerImpl::foldIntrinsicIsFPClass(IntrinsicInst &II) {
   return nullptr;
 }
 
-static std::optional<bool> getKnownSign(Value *Op, Instruction *CxtI,
-                                   const DataLayout &DL, AssumptionCache *AC,
-                                   DominatorTree *DT) {
-  KnownBits Known = computeKnownBits(Op, DL, 0, AC, CxtI, DT);
+static std::optional<bool> getKnownSign(Value *Op, const SimplifyQuery &SQ) {
+  KnownBits Known = computeKnownBits(Op, /*Depth=*/0, SQ);
   if (Known.isNonNegative())
     return false;
   if (Known.isNegative())
     return true;
 
   Value *X, *Y;
   if (match(Op, m_NSWSub(m_Value(X), m_Value(Y))))
-    return isImpliedByDomCondition(ICmpInst::ICMP_SLT, X, Y, CxtI, DL);
+    return isImpliedByDomCondition(ICmpInst::ICMP_SLT, X, Y, SQ.CxtI, SQ.DL);
 
-  return isImpliedByDomCondition(
-      ICmpInst::ICMP_SLT, Op, Constant::getNullValue(Op->getType()), CxtI, DL);
+  return std::nullopt;
 }
 
-static std::optional<bool> getKnownSignOrZero(Value *Op, Instruction *CxtI,
-                                              const DataLayout &DL,
-                                              AssumptionCache *AC,
-                                              DominatorTree *DT) {
-  if (std::optional<bool> Sign = getKnownSign(Op, CxtI, DL, AC, DT))
+static std::optional<bool> getKnownSignOrZero(Value *Op,
+                                              const SimplifyQuery &SQ) {
+  if (std::optional<bool> Sign = getKnownSign(Op, SQ))
     return Sign;
 
   Value *X, *Y;
   if (match(Op, m_NSWSub(m_Value(X), m_Value(Y))))
-    return isImpliedByDomCondition(ICmpInst::ICMP_SLE, X, Y, CxtI, DL);
+    return isImpliedByDomCondition(ICmpInst::ICMP_SLE, X, Y, SQ.CxtI, SQ.DL);
 
   return std::nullopt;
 }
 
 /// Return true if two values \p Op0 and \p Op1 are known to have the same sign.
-static bool signBitMustBeTheSame(Value *Op0, Value *Op1, Instruction *CxtI,
-                                 const DataLayout &DL, AssumptionCache *AC,
-                                 DominatorTree *DT) {
-  std::optional<bool> Known1 = getKnownSign(Op1, CxtI, DL, AC, DT);
+static bool signBitMustBeTheSame(Value *Op0, Value *Op1,
+                                 const SimplifyQuery &SQ) {
+  std::optional<bool> Known1 = getKnownSign(Op1, SQ);
   if (!Known1)
     return false;
-  std::optional<bool> Known0 = getKnownSign(Op0, CxtI, DL, AC, DT);
+  std::optional<bool> Known0 = getKnownSign(Op0, SQ);
   if (!Known0)
     return false;
   return *Known0 == *Known1;
@@ -1628,7 +1622,7 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
     }
 
     if (std::optional<bool> Known =
-            getKnownSignOrZero(IIOperand, II, DL, &AC, &DT)) {
+            getKnownSignOrZero(IIOperand, SQ.getWithInstruction(II))) {
       // abs(x) -> x if x >= 0 (include abs(x-y) --> x - y where x >= y)
       // abs(x) -> x if x > 0 (include abs(x-y) --> x - y where x > y)
       if (!*Known)
@@ -1753,7 +1747,7 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
       bool UseAndN = IID == Intrinsic::smin || IID == Intrinsic::umin;
 
       if (IID == Intrinsic::smax || IID == Intrinsic::smin) {
-        auto KnownSign = getKnownSign(X, II, DL, &AC, &DT);
+        auto KnownSign = getKnownSign(X, SQ.getWithInstruction(II));
         if (KnownSign == std::nullopt) {
           UseOr = false;
           UseAndN = false;
@@ -2614,7 +2608,7 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
       FastMathFlags InnerFlags = cast<FPMathOperator>(Src)->getFastMathFlags();
 
       if ((FMF.allowReassoc() && InnerFlags.allowReassoc()) ||
-          signBitMustBeTheSame(Exp, InnerExp, II, DL, &AC, &DT)) {
+          signBitMustBeTheSame(Exp, InnerExp, SQ.getWithInstruction(II))) {
         // TODO: Add nsw/nuw probably safe if integer type exceeds exponent
         // width.
         Value *NewExp = Builder.CreateAdd(InnerExp, Exp);