Subzero: Consider all instruction variables for register preference.

src/IceInstX86Base.h

 //===- subzero/src/IceInstX86Base.h - Generic x86 instructions -*- C++ -*--===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 959 matching lines @@
   InstX86BaseMovlike() = delete;
   InstX86BaseMovlike(const InstX86BaseMovlike &) = delete;
   InstX86BaseMovlike &operator=(const InstX86BaseMovlike &) = delete;
 
 public:
   using Base = InstX86BaseMovlike<Machine, K>;
 
   bool isRedundantAssign() const override {
     return checkForRedundantAssign(this->getDest(), this->getSrc(0));
   }
-  bool isSimpleAssign() const override { return true; }
+  bool isVarAssign() const override {
+    return llvm::isa<Variable>(this->getSrc(0));
+  }
   void dump(const Cfg *Func) const override {
     if (!BuildDefs::dump())
       return;
     Ostream &Str = Func->getContext()->getStrDump();
     Str << Opcode << "." << this->getDest()->getType() << " ";
     this->dumpDest(Func);
     Str << ", ";
     this->dumpSources(Func);
   }
   static bool classof(const Inst *Inst) {
@@ skipping 2228 matching lines @@
           &InstX86Base<Machine>::Traits::Assembler::psrl};                     \
   }                                                                            \
   }
 
 } // end of namespace X86Internal
 } // end of namespace Ice
 
 #include "IceInstX86BaseImpl.h"
 
 #endif // SUBZERO_SRC_ICEINSTX86BASE_H