[clang] NFC: Dead code removal in SemaDecl.cpp, CheckMultiVersionFunction().

[tahonermann]

Summary

This change removes dead code in the definition of CheckMultiVersionFunction()
in clang/lib/Sema/SemaDecl.cpp. The removed code was made dead by commit
fc53eb69c26cdd7efa6b629c187d04326f0448ca: "Reapply 'Implement target_clones multiversioning'".
See the added code just above the code being deleted; it contains the same
return statement with the previous condition now distributed across an if
statement and a switch statement.

[tahonermann]

clang/lib/Sema/SemaDecl.cpp

10918–10920

These lines are what makes the removed code dead code.

[aaron.ballman]

LGTM!

clang/lib/Sema/SemaDecl.cpp

S.Diag(NewFD->getLocation(), diag::err_multiversion_required_in_redecl)
         << (OldFD->getMultiVersionKind() != MultiVersionKind::Target);
     NewFD->setInvalidDecl();
     return true;
   }
 
   if (!OldFD->isMultiVersion()) {
     switch (MVType) {
     case MultiVersionKind::Target:
       return CheckTargetCausesMultiVersioning(S, OldFD, NewFD, NewTA,
                                               Redeclaration, OldDecl,
                                               MergeTypeWithPrevious, Previous);
     case MultiVersionKind::TargetClones:
       if (OldFD->isUsed(false)) {
         NewFD->setInvalidDecl();
         return S.Diag(NewFD->getLocation(), diag::err_multiversion_after_used);
       }
       OldFD->setIsMultiVersion();
       break;
     case MultiVersionKind::CPUDispatch:
     case MultiVersionKind::CPUSpecific:
     case MultiVersionKind::None:
       break;
     }
   }
-  // Handle the target potentially causes multiversioning case.
-  if (!OldFD->isMultiVersion() && MVType == MultiVersionKind::Target)
-    return CheckTargetCausesMultiVersioning(S, OldFD, NewFD, NewTA,
-                                            Redeclaration, OldDecl,
-                                            MergeTypeWithPrevious, Previous);
 
   // At this point, we have a multiversion function decl (in OldFD) AND an
   // appropriate attribute in the current function decl.  Resolve that these are
   // still compatible with previous declarations.
   return CheckMultiVersionAdditionalDecl(
       S, OldFD, NewFD, MVType, NewTA, NewCPUDisp, NewCPUSpec, NewClones,
       Redeclaration, OldDecl, MergeTypeWithPrevious, Previous);
 }