[IRCE][NFC] Remove unused variable IsSigned

[mkazantsev]

:)

llvm/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp

 class InductiveRangeCheck {
 
   const SCEV *Begin = nullptr;
   const SCEV *Step = nullptr;
   const SCEV *End = nullptr;
   Use *CheckUse = nullptr;
 
   static bool parseRangeCheckICmp(Loop *L, ICmpInst *ICI, ScalarEvolution &SE,
-                                  Value *&Index, Value *&Length,
-                                  bool &IsSigned);
+                                  Value *&Index, Value *&Length);
 
   static void
   extractRangeChecksFromCond(Loop *L, ScalarEvolution &SE, Use &ConditionUse,
                              SmallVectorImpl<InductiveRangeCheck> &Checks,
                              SmallPtrSetImpl<Value *> &Visited);
 
 public:
   const SCEV *getBegin() const { return Begin; }

 
 /// Parse a single ICmp instruction, `ICI`, into a range check.  If `ICI` cannot
 /// be interpreted as a range check, return false and set `Index` and `Length`
 /// to `nullptr`.  Otherwise set `Index` to the value being range checked, and
 /// set `Length` to the upper limit `Index` is being range checked.
 bool
 InductiveRangeCheck::parseRangeCheckICmp(Loop *L, ICmpInst *ICI,
                                          ScalarEvolution &SE, Value *&Index,
-                                         Value *&Length, bool &IsSigned) {
+                                         Value *&Length) {
   auto IsLoopInvariant = [&SE, L](Value *V) {
     return SE.isLoopInvariant(SE.getSCEV(V), L);
   };
 
   ICmpInst::Predicate Pred = ICI->getPredicate();
   Value *LHS = ICI->getOperand(0);
   Value *RHS = ICI->getOperand(1);
 
   switch (Pred) {
   default:
     return false;
 
   case ICmpInst::ICMP_SLE:
     std::swap(LHS, RHS);
     [[fallthrough]];
   case ICmpInst::ICMP_SGE:
-    IsSigned = true;
     if (match(RHS, m_ConstantInt<0>())) {
       Index = LHS;
       return true; // Lower.
     }
     return false;
 
   case ICmpInst::ICMP_SLT:
     std::swap(LHS, RHS);
     [[fallthrough]];
   case ICmpInst::ICMP_SGT:
-    IsSigned = true;
     if (match(RHS, m_ConstantInt<-1>())) {
       Index = LHS;
       return true; // Lower.
     }
 
     if (IsLoopInvariant(LHS)) {
       Index = RHS;
       Length = LHS;
       return true; // Upper.
     }
     return false;
 
   case ICmpInst::ICMP_ULT:
     std::swap(LHS, RHS);
     [[fallthrough]];
   case ICmpInst::ICMP_UGT:
-    IsSigned = false;
     if (IsLoopInvariant(LHS)) {
       Index = RHS;
       Length = LHS;
       return true; // Both lower and upper.
     }
     return false;
   }
 
if (match(Condition, m_LogicalAnd(m_Value(), m_Value()))) {
     return;
   }
 
   ICmpInst *ICI = dyn_cast<ICmpInst>(Condition);
   if (!ICI)
     return;
 
   Value *Length = nullptr, *Index;
-  bool IsSigned;
-  if (!parseRangeCheckICmp(L, ICI, SE, Index, Length, IsSigned))
+  if (!parseRangeCheckICmp(L, ICI, SE, Index, Length))
     return;
 
   const auto *IndexAddRec = dyn_cast<SCEVAddRecExpr>(SE.getSCEV(Index));
   bool IsAffineIndex =
       IndexAddRec && (IndexAddRec->getLoop() == L) && IndexAddRec->isAffine();
 
   if (!IsAffineIndex)
     return;