Make helper functions static or move them into anonymous namespaces.  NFC.
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 7b2b033..09fd308 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -14260,6 +14260,7 @@
   }
 }
 
+namespace {
 struct BuiltinAlignArgs {
   llvm::Value *Src = nullptr;
   llvm::Type *SrcType = nullptr;
@@ -14288,6 +14289,7 @@
     Mask = CGF.Builder.CreateSub(Alignment, One, "mask");
   }
 };
+} // namespace
 
 /// Generate (x & (y-1)) == 0.
 RValue CodeGenFunction::EmitBuiltinIsAligned(const CallExpr *E) {