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

src/IceTargetLowering.cpp

 //===- subzero/src/IceTargetLowering.cpp - Basic lowering implementation --===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 422 matching lines @@
 
 InstCall *TargetLowering::makeHelperCall(const IceString &Name, Variable *Dest,
                                          SizeT MaxSrcs) {
   const bool HasTailCall = false;
   Constant *CallTarget = Ctx->getConstantExternSym(Name);
   InstCall *Call =
       InstCall::create(Func, MaxSrcs, Dest, CallTarget, HasTailCall);
   return Call;
 }
 
+bool TargetLowering::shouldOptimizeMemIntrins() {
+  return Ctx->getFlags().getOptLevel() >= Opt_1 ||
+         Ctx->getFlags().getForceMemIntrinOpt();
+}
+
 void TargetLowering::emitWithoutPrefix(const ConstantRelocatable *C) const {
   if (!BuildDefs::dump())
     return;
   Ostream &Str = Ctx->getStrEmit();
   if (C->getSuppressMangling())
     Str << C->getName();
   else
     Str << Ctx->mangleName(C->getName());
   RelocOffsetT Offset = C->getOffset();
   if (Offset) {
@@ skipping 140 matching lines @@
   if (Target == Target_##X)                                                    \
     return TargetHeader##X::create(Ctx);
 #include "llvm/Config/SZTargets.def"
 
   llvm::report_fatal_error("Unsupported target header lowering");
 }
 
 TargetHeaderLowering::~TargetHeaderLowering() = default;
 
 } // end of namespace Ice