Subzero: Clean up some uses of *_cast<>.

src/IceInst.cpp

 //===- subzero/src/IceInst.cpp - High-level instruction implementation ----===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 262 matching lines @@
 }
 
 IceString InstArithmetic::getInstName() const {
   if (!BuildDefs::dump())
     return "???";
 
   return InstArithmeticAttributes[getOp()].DisplayString;
 }
 
 const char *InstArithmetic::getOpName(OpKind Op) {
-  size_t OpIndex = static_cast<size_t>(Op);
-  return OpIndex < InstArithmetic::_num
-             ? InstArithmeticAttributes[OpIndex].DisplayString
-             : "???";
+  return Op < InstArithmetic::_num ? InstArithmeticAttributes[Op].DisplayString
+                                   : "???";
 }
 
 bool InstArithmetic::isCommutative() const {
   return InstArithmeticAttributes[getOp()].IsCommutative;
 }
 
 InstAssign::InstAssign(Cfg *Func, Variable *Dest, Operand *Source)
     : InstHighLevel(Func, Inst::Assign, 1, Dest) {
   addSource(Source);
 }
@@ skipping 425 matching lines @@
   for (SizeT I = 0; I < getNumArgs(); ++I) {
     if (I > 0)
       Str << ", ";
     Str << getArg(I)->getType() << " ";
     getArg(I)->dump(Func);
   }
   Str << ")";
 }
 
 const char *InstCast::getCastName(InstCast::OpKind Kind) {
-  size_t Index = static_cast<size_t>(Kind);
-  if (Index < InstCast::OpKind::_num)
-    return InstCastAttributes[Index].DisplayString;
+  if (Kind < InstCast::OpKind::_num)
+    return InstCastAttributes[Kind].DisplayString;
   llvm_unreachable("Invalid InstCast::OpKind");
   return "???";
 }
 
 void InstCast::dump(const Cfg *Func) const {
   if (!BuildDefs::dump())
     return;
   Ostream &Str = Func->getContext()->getStrDump();
   dumpDest(Func);
   Str << " = " << getCastName(getCastKind()) << " " << getSrc(0)->getType()
@@ skipping 267 matching lines @@
     // upper 32 bits of rax. We need to recognize and preserve these.
     return true;
   }
   if (!Dest->hasReg() && !SrcVar->hasReg() &&
       Dest->getStackOffset() == SrcVar->getStackOffset())
     return true;
   return false;
 }
 
 } // end of namespace Ice