Subzero: Use "auto" per (unwritten) auto coding style.

src/IceTargetLoweringX8664.cpp

 //===- subzero/src/IceTargetLoweringX8664.cpp - x86-64 lowering -----------===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 765 matching lines @@
     Operand::OperandKind K = (*Pool.begin())->getKind();
     RandomNumberGenerator RNG(Ctx->getFlags().getRandomSeed(),
                               RPE_PooledConstantReordering, K);
     RandomShuffle(Pool.begin(), Pool.end(),
                   [&RNG](uint64_t N) { return (uint32_t)RNG.next(N); });
   }
 
   for (Constant *C : Pool) {
     if (!C->getShouldBePooled())
       continue;
-    typename T::IceType *Const = llvm::cast<typename T::IceType>(C);
+    auto *Const = llvm::cast<typename T::IceType>(C);
     typename T::IceType::PrimType Value = Const->getValue();
     // Use memcpy() to copy bits from Value into RawValue in a way that avoids
     // breaking strict-aliasing rules.
     typename T::PrimitiveIntType RawValue;
     memcpy(&RawValue, &Value, sizeof(Value));
     char buf[30];
     int CharsPrinted =
         snprintf(buf, llvm::array_lengthof(buf), T::PrintfString, RawValue);
     assert(CharsPrinted >= 0 &&
            (size_t)CharsPrinted < llvm::array_lengthof(buf));
@@ skipping 182 matching lines @@
 // case the high-level table has extra entries.
 #define X(tag, sizeLog2, align, elts, elty, str)                               \
   static_assert(_table1_##tag == _table2_##tag,                                \
                 "Inconsistency between ICETYPEX8664_TABLE and ICETYPE_TABLE");
 ICETYPE_TABLE
 #undef X
 } // end of namespace dummy3
 } // end of anonymous namespace
 
 } // end of namespace Ice