Fix build warnings

src/IceTargetLoweringX8632.cpp

 //===- subzero/src/IceTargetLoweringX8632.cpp - x86-32 lowering -----------===//
 //
 //                        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 TargetLoweringX8632 class, which
@@ skipping 4692 matching lines @@
         Str << Reloc->getDeclaration()->mangleName(Ctx);
         if (RelocOffsetT Offset = Reloc->getOffset()) {
           if (Offset >= 0 || (Offset == INT32_MIN))
             Str << " + " << Offset;
           else
             Str << " - " << -Offset;
         }
         Str << "\n";
         break;
       }
-      default: {
-        std::string Buffer;
-        llvm::raw_string_ostream StrBuf(Buffer);
-        StrBuf << "Unable to lower initializer: ";
-        Init->dump(StrBuf);
-        llvm::report_fatal_error(StrBuf.str());
-        break;
-      }
       }
     }
   } else if (IsConstant || IsExternal)
     Str << "\t.zero\t" << Size << "\n";
   // Size is part of .comm.
 
   if (IsConstant || HasNonzeroInitializer || IsExternal)
     Str << "\t.size\t" << MangledName << ", " << Size << "\n";
   // Size is part of .comm.
 }
 
 } // end of namespace Ice