Subzero: Fix over-aggressive bool folding.

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 170 matching lines @@
       LREndedBits RightMask = OrigInst->LiveRangesEnded >> (Index + 1);
       LiveRangesEnded = LeftMask | (SpliceAssn->LiveRangesEnded << Index) |
                         (RightMask << (Index + getSrc(I)->getNumVars()));
       return;
     }
     Index += getSrc(I)->getNumVars();
   }
   llvm::report_fatal_error("Failed to find splice operand");
 }
 
+bool Inst::isMemoryWrite() const {
+  llvm::report_fatal_error("Attempt to call base Inst::isMemoryWrite() method");
+}
+
 void Inst::livenessLightweight(Cfg *Func, LivenessBV &Live) {
   assert(!isDeleted());
   resetLastUses();
   VariablesMetadata *VMetadata = Func->getVMetadata();
   FOREACH_VAR_IN_INST(Var, *this) {
     if (VMetadata->isMultiBlock(Var))
       continue;
     SizeT Index = Var->getIndex();
     if (Live[Index])
       continue;
@@ skipping 861 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