Fix warnings produced by g++ on Windows.

src/IceCfgNode.cpp

 //===- subzero/src/IceCfgNode.cpp - Basic block (node) implementation -----===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 223 matching lines @@
   bool Found = false;
   for (CfgNode *&I : Pred->OutEdges) {
     if (I == this) {
       I = NewNode;
       NewNode->InEdges.push_back(Pred);
       Found = true;
       break;
     }
   }
   assert(Found);
+  (void)Found;
   // Repoint this node's in-edge.
   Found = false;
   for (CfgNode *&I : InEdges) {
     if (I == Pred) {
       I = NewNode;
       NewNode->OutEdges.push_back(this);
       Found = true;
       break;
     }
   }
   assert(Found);
+  (void)Found;
   // Repoint all suitable branch instructions' target and return.
   Found = false;
   for (Inst &I : Pred->getInsts())
     if (!I.isDeleted() && I.repointEdges(this, NewNode))
       Found = true;
   assert(Found);
+  (void)Found;
   return NewNode;
 }
 
 namespace {
 
 // Helper function used by advancedPhiLowering().
 bool sameVarOrReg(const Variable *Var, const Operand *Opnd) {
   if (Var == Opnd)
     return true;
   if (const auto Var2 = llvm::dyn_cast<Variable>(Opnd)) {
@@ skipping 1009 matching lines @@
   InstIntrinsicCall *Inst = InstIntrinsicCall::create(
       Func, 5, Func->makeVariable(IceType_i64), RMWI64Name, Info->Info);
   Inst->addArg(AtomicRMWOp);
   Inst->addArg(Counter);
   Inst->addArg(One);
   Inst->addArg(OrderAcquireRelease);
   Insts.push_front(Inst);
 }
 
 } // end of namespace Ice