Subzero: Improve the representation and handling of the FakeKill instruction.

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.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements the CfgNode class, including the complexities
@@ skipping 649 matching lines @@
       continue;
     if (FirstInstNum == Inst::NumberSentinel)
       FirstInstNum = I->getNumber();
     assert(I->getNumber() > LastInstNum);
     LastInstNum = I->getNumber();
     // Create fake live ranges for a Kill instruction, but only if the
     // linked instruction is still alive.
     if (Mode == Liveness_Intervals) {
       if (InstFakeKill *Kill = llvm::dyn_cast<InstFakeKill>(I)) {
         if (!Kill->getLinked()->isDeleted()) {
-          SizeT NumSrcs = I->getSrcSize();
-          for (SizeT Src = 0; Src < NumSrcs; ++Src) {
-            Variable *Var = llvm::cast<Variable>(I->getSrc(Src));
+          for (Variable *Var : Kill->getKilledRegs()) {
             InstNumberT InstNumber = I->getNumber();
             Var->addLiveRange(InstNumber, InstNumber, 1);
           }
         }
       }
     }
   }
   if (Mode != Liveness_Intervals)
     return;
   TimerMarker T1(TimerStack::TT_liveRangeCtor, Func);
@@ skipping 311 matching lines @@
       if (!First)
         Str << ", ";
       First = false;
       Str << "%" << I->getName();
     }
     Str << "\n";
   }
 }
 
 } // end of namespace Ice