Use separate random number generator for each randomization pass

src/IceTargetLowering.cpp

 //===- subzero/src/IceTargetLowering.cpp - Basic lowering implementation --===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 85 matching lines @@
 
 void TargetLowering::doAddressOpt() {
   if (llvm::isa<InstLoad>(*Context.getCur()))
     doAddressOptLoad();
   else if (llvm::isa<InstStore>(*Context.getCur()))
     doAddressOptStore();
   Context.advanceCur();
   Context.advanceNext();
 }
 
-void TargetLowering::doNopInsertion() {
+void TargetLowering::doNopInsertion(RandomNumberGenerator &RNG) {
   Inst *I = Context.getCur();
   bool ShouldSkip = llvm::isa<InstFakeUse>(I) || llvm::isa<InstFakeDef>(I) ||
                     llvm::isa<InstFakeKill>(I) || I->isRedundantAssign() ||
                     I->isDeleted();
   if (!ShouldSkip) {
     int Probability = Ctx->getFlags().getNopProbabilityAsPercentage();
     for (int I = 0; I < Ctx->getFlags().getMaxNopsPerInstruction(); ++I) {
-      randomlyInsertNop(Probability / 100.0);
+      randomlyInsertNop(Probability / 100.0, RNG);
     }
   }
 }
 
 // Lowers a single instruction according to the information in
 // Context, by checking the Context.Cur instruction kind and calling
 // the appropriate lowering method.  The lowering method should insert
 // target instructions at the Cur.Next insertion point, and should not
 // delete the Context.Cur instruction or advance Context.Cur.
 //
@@ skipping 468 matching lines @@
   if (Target == Target_##X)                                                    \
     return TargetHeader##X::create(Ctx);
 #include "llvm/Config/SZTargets.def"
 
   llvm::report_fatal_error("Unsupported target header lowering");
 }
 
 TargetHeaderLowering::~TargetHeaderLowering() = default;
 
 } // end of namespace Ice