Inline memove for small constant sizes and refactor memcpy and memset.

src/IceInstX86BaseImpl.h

 //===- subzero/src/IceInstX86BaseImpl.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 3125 matching lines @@
   Str << ", ";
   this->getSrc(0)->emit(Func);
 }
 
 template <class Machine>
 void InstX86Xchg<Machine>::emitIAS(const Cfg *Func) const {
   assert(this->getSrcSize() == 2);
   typename InstX86Base<Machine>::Traits::Assembler *Asm =
       Func->getAssembler<typename InstX86Base<Machine>::Traits::Assembler>();
   Type Ty = this->getSrc(0)->getType();
+  const auto VarReg1 = llvm::cast<Variable>(this->getSrc(1));
+  assert(VarReg1->hasReg());
+  const typename InstX86Base<Machine>::Traits::RegisterSet::GPRRegister Reg1 =
+      InstX86Base<Machine>::Traits::RegisterSet::getEncodedGPR(
+          VarReg1->getRegNum());
+
+  if (const auto VarReg0 = llvm::dyn_cast<Variable>(this->getSrc(0))) {
+    assert(VarReg0->hasReg());
+    const typename InstX86Base<Machine>::Traits::RegisterSet::GPRRegister Reg0 =
+        InstX86Base<Machine>::Traits::RegisterSet::getEncodedGPR(
+            VarReg0->getRegNum());
+    Asm->xchg(Ty, Reg0, Reg1);
+    return;
+  }
+
   const auto Mem =
       llvm::cast<typename InstX86Base<Machine>::Traits::X86OperandMem>(
           this->getSrc(0));
   assert(Mem->getSegmentRegister() ==
          InstX86Base<Machine>::Traits::X86OperandMem::DefaultSegment);
   const typename InstX86Base<Machine>::Traits::Address Addr =
       Mem->toAsmAddress(Asm);
-  const auto VarReg = llvm::cast<Variable>(this->getSrc(1));
-  assert(VarReg->hasReg());
-  const typename InstX86Base<Machine>::Traits::RegisterSet::GPRRegister Reg =
-      InstX86Base<Machine>::Traits::RegisterSet::getEncodedGPR(
-          VarReg->getRegNum());
-  Asm->xchg(Ty, Addr, Reg);
+  Asm->xchg(Ty, Addr, Reg1);
 }
 
 template <class Machine>
 void InstX86Xchg<Machine>::dump(const Cfg *Func) const {
   if (!BuildDefs::dump())
     return;
   Ostream &Str = Func->getContext()->getStrDump();
   Type Ty = this->getSrc(0)->getType();
   Str << "xchg." << Ty << " ";
   this->dumpSources(Func);
@@ skipping 49 matching lines @@
     return;
   Ostream &Str = Func->getContext()->getStrDump();
   Str << "IACA_END";
 }
 
 } // end of namespace X86Internal
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEINSTX86BASEIMPL_H