[NFC] Avoid some AttrBuilder redundant initialization

[serge-sans-paille]

Summary

When compiling sqlite amalgamation, this drops instruction count
from 5,871,802,226, to 5,867,475,615, which is not very significant but not
something to be frowned upon either.

[nikic]

Wouldn't this go against https://llvm.org/docs/CodingStandards.html#do-not-use-static-constructors?

[nikic]

This one can probably be abandoned after the AttrMask/AttrBuilder changes that have been made?

clang/lib/CodeGen/CodeGenModule.cpp

if (!Features.empty()) {
     llvm::sort(Features);
     Attrs.addAttribute("target-features", llvm::join(Features, ","));
     AddedAttr = true;
   }
 
   return AddedAttr;
 }
 
+static llvm::AttrBuilder setNonAliasAttributesRemoveAttrs =
+    llvm::AttrBuilder()
+        .addAttribute("target-cpu")
+        .addAttribute("target-features")
+        .addAttribute("tune-cpu");
+
 void CodeGenModule::setNonAliasAttributes(GlobalDecl GD,
                                           llvm::GlobalObject *GO) {
   const Decl *D = GD.getDecl();
   SetCommonAttributes(GD, GO);
 
   if (D) {
     if (auto *GV = dyn_cast<llvm::GlobalVariable>(GO)) {
       if (D->hasAttr<RetainAttr>())
if (auto *F = dyn_cast<llvm::Function>(GO)) {
         if (!D->getAttr<SectionAttr>())
           F->addFnAttr("implicit-section-name", SA->getName());
 
       llvm::AttrBuilder Attrs;
       if (GetCPUAndFeaturesAttributes(GD, Attrs)) {
         // We know that GetCPUAndFeaturesAttributes will always have the
         // newest set, since it has the newest possible FunctionDecl, so the
         // new ones should replace the old.
-        llvm::AttrBuilder RemoveAttrs;
-        RemoveAttrs.addAttribute("target-cpu");
-        RemoveAttrs.addAttribute("target-features");
-        RemoveAttrs.addAttribute("tune-cpu");
-        F->removeFnAttrs(RemoveAttrs);
+        F->removeFnAttrs(setNonAliasAttributesRemoveAttrs);
         F->addFnAttrs(Attrs);
       }
     }
 
     if (const auto *CSA = D->getAttr<CodeSegAttr>())
       GO->setSection(CSA->getName());
     else if (const auto *SA = D->getAttr<SectionAttr>())
       GO->setSection(SA->getName());