[Clang] Add noalias to this pointer in C++ constructors

Author: guy-david

clang/lib/CodeGen/CodeGenFunction.cpp

@@ -1567,8 +1567,10 @@ void CodeGenFunction::GenerateCode(GlobalDecl GD, llvm::Function *Fn,
   PGO.assignRegionCounters(GD, CurFn);
   if (isa<CXXDestructorDecl>(FD))
     EmitDestructorBody(Args);
-  else if (isa<CXXConstructorDecl>(FD))
+  else if (isa<CXXConstructorDecl>(FD)) {
+    Fn->addParamAttr(0, llvm::Attribute::NoAlias);
     EmitConstructorBody(Args);
+  }
   else if (getLangOpts().CUDA &&
            !getLangOpts().CUDAIsDevice &&
            FD->hasAttr<CUDAGlobalAttr>())