Add option to force filetype=asm for testing

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 394 matching lines @@
 
     Args[i] = RegisterArg;
     Context.insert<InstAssign>(Arg, RegisterArg);
   }
 }
 
 void TargetX8664::lowerRet(const InstRet *Inst) {
   Variable *Reg = nullptr;
   if (Inst->hasRetValue()) {
     Operand *Src0 = legalize(Inst->getRetValue());
-    if (isVectorType(Src0->getType()) ||
-        isScalarFloatingType(Src0->getType())) {
+    const Type Src0Ty = Src0->getType();
+    if (isVectorType(Src0Ty) || isScalarFloatingType(Src0Ty)) {
       Reg = legalizeToReg(Src0, Traits::RegisterSet::Reg_xmm0);
     } else {
-      assert(isScalarIntegerType(Src0->getType()));
-      _mov(Reg, Src0, Traits::getGprForType(Src0->getType(),
-                                            Traits::RegisterSet::Reg_rax));
+      assert(isScalarIntegerType(Src0Ty));
+      _mov(Reg, Src0,
+           Traits::getGprForType(Src0Ty, Traits::RegisterSet::Reg_rax));
     }
   }
   // Add a ret instruction even if sandboxing is enabled, because addEpilog
   // explicitly looks for a ret instruction as a marker for where to insert the
   // frame removal instructions.
   _ret(Reg);
   // Add a fake use of esp to make sure esp stays alive for the entire
   // function. Otherwise post-call esp adjustments get dead-code eliminated.
   keepEspLiveAtExit();
 }
@@ skipping 618 matching lines @@
 #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 X8664
 } // end of namespace Ice