Subzero: Find rematerializable variables transitively.

src/IceTargetLoweringX86BaseImpl.h

 //===- subzero/src/IceTargetLoweringX86BaseImpl.h - x86 lowering -*- C++ -*-==//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 1299 matching lines @@
     //   a.hi = t3
     Context.insert(Label);
     _mov(DestLo, T_2);
     _mov(DestHi, T_3);
   }
 }
 
 template <class Machine>
 void TargetX86Base<Machine>::lowerArithmetic(const InstArithmetic *Inst) {
   Variable *Dest = Inst->getDest();
+  if (Dest->isRematerializable()) {
+    Context.insert(InstFakeDef::create(Func, Dest));
+    return;
+  }
   Type Ty = Dest->getType();
   Operand *Src0 = legalize(Inst->getSrc(0));
   Operand *Src1 = legalize(Inst->getSrc(1));
   if (Inst->isCommutative()) {
     uint32_t SwapCount = 0;
     if (!llvm::isa<Variable>(Src0) && llvm::isa<Variable>(Src1)) {
       std::swap(Src0, Src1);
       ++SwapCount;
     }
     if (llvm::isa<Constant>(Src0) && !llvm::isa<Constant>(Src1)) {
@@ skipping 560 matching lines @@
     Call->addArg(Src0);
     Call->addArg(Src1);
     return lowerCall(Call);
   }
   }
 }
 
 template <class Machine>
 void TargetX86Base<Machine>::lowerAssign(const InstAssign *Inst) {
   Variable *Dest = Inst->getDest();
+  if (Dest->isRematerializable()) {
+    Context.insert(InstFakeDef::create(Func, Dest));
+    return;
+  }
   Operand *Src0 = Inst->getSrc(0);
   assert(Dest->getType() == Src0->getType());
   if (!Traits::Is64Bit && Dest->getType() == IceType_i64) {
     Src0 = legalize(Src0);
     Operand *Src0Lo = loOperand(Src0);
     Operand *Src0Hi = hiOperand(Src0);
     Variable *DestLo = llvm::cast<Variable>(loOperand(Dest));
     Variable *DestHi = llvm::cast<Variable>(hiOperand(Dest));
     Variable *T_Lo = nullptr, *T_Hi = nullptr;
     _mov(T_Lo, Src0Lo);
@@ skipping 4068 matching lines @@
   }
   // the offset is not eligible for blinding or pooling, return the original
   // mem operand
   return MemOperand;
 }
 
 } // end of namespace X86Internal
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICETARGETLOWERINGX86BASEIMPL_H