Subzero: Consider all instruction variables for register preference.

src/IceInstARM32.h

 //===- subzero/src/IceInstARM32.h - ARM32 machine 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 1134 matching lines @@
 public:
   static InstARM32Mov *create(Cfg *Func, Variable *Dest, Operand *Src,
                               CondARM32::Cond Predicate) {
     return new (Func->allocate<InstARM32Mov>())
         InstARM32Mov(Func, Dest, Src, Predicate);
   }
   bool isRedundantAssign() const override {
     return !isMultiDest() && !isMultiSource() &&
            checkForRedundantAssign(getDest(), getSrc(0));
   }
-  bool isSimpleAssign() const override { return true; }
+  bool isVarAssign() const override { return llvm::isa<Variable>(getSrc(0)); }

[John, 2015/10/12 15:35:16]

this method is inline, but the other is not. does it matter?

[Jim Stichnoth, 2015/10/12 17:27:31]

The implementation of InstAssign::isVarAssign() had to be moved into the .cpp
file, instead of being inline, because the Variable class definition wasn't yet
available.

That turns out not to be the case in these IceInst*.h files, so I'll keep it
inline until it breaks...

   void emit(const Cfg *Func) const override;
   void emitIAS(const Cfg *Func) const override;
   void dump(const Cfg *Func) const override;
   static bool classof(const Inst *Inst) { return isClassof(Inst, Mov); }
 
   bool isMultiDest() const { return DestHi != nullptr; }
 
   bool isMultiSource() const {
     assert(getSrcSize() == 1 || getSrcSize() == 2);
     return getSrcSize() == 2;
@@ skipping 95 matching lines @@
 // default implementations. Without this, there is the possibility of ODR
 // violations and link errors.
 
 template <> void InstARM32Ldr::emit(const Cfg *Func) const;
 template <> void InstARM32Movw::emit(const Cfg *Func) const;
 template <> void InstARM32Movt::emit(const Cfg *Func) const;
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEINSTARM32_H