diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index b0b64328b84e..ae0aca09ea4a 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -2087,6 +2087,24 @@ void CodeGenModule::ConstructAttributeList(StringRef Name,
       // allows it to work on indirect virtual function calls.
       if (AttrOnCallSite && TargetDecl->hasAttr<NoMergeAttr>())
         FuncAttrs.addAttribute(llvm::Attribute::NoMerge);
+
+      // Add known guaranteed alignment for allocation functions.
+      if (unsigned BuiltinID = Fn->getBuiltinID()) {
+        switch (BuiltinID) {
+        case Builtin::BIaligned_alloc:
+        case Builtin::BIcalloc:
+        case Builtin::BImalloc:
+        case Builtin::BImemalign:
+        case Builtin::BIrealloc:
+        case Builtin::BIstrdup:
+        case Builtin::BIstrndup:
+          RetAttrs.addAlignmentAttr(Context.getTargetInfo().getNewAlign() /
+                                    Context.getTargetInfo().getCharWidth());
+          break;
+        default:
+          break;
+        }
+      }
     }
 
     // 'const', 'pure' and 'noalias' attributed functions are also nounwind.
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 506af5d1458c..5c22df026a7d 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -15215,30 +15215,6 @@ void Sema::AddKnownFunctionAttributes(FunctionDecl *FD) {
       else
         FD->addAttr(CUDAHostAttr::CreateImplicit(Context, FD->getLocation()));
     }
-
-    // Add known guaranteed alignment for allocation functions.
-    switch (BuiltinID) {
-    case Builtin::BIaligned_alloc:
-    case Builtin::BIcalloc:
-    case Builtin::BImalloc:
-    case Builtin::BImemalign:
-    case Builtin::BIrealloc:
-    case Builtin::BIstrdup:
-    case Builtin::BIstrndup: {
-      if (!FD->hasAttr<AssumeAlignedAttr>()) {
-        unsigned NewAlign = Context.getTargetInfo().getNewAlign() /
-                            Context.getTargetInfo().getCharWidth();
-        IntegerLiteral *Alignment = IntegerLiteral::Create(
-            Context, Context.MakeIntValue(NewAlign, Context.UnsignedIntTy),
-            Context.UnsignedIntTy, FD->getLocation());
-        FD->addAttr(AssumeAlignedAttr::CreateImplicit(
-            Context, Alignment, /*Offset=*/nullptr, FD->getLocation()));
-      }
-      break;
-    }
-    default:
-      break;
-    }
   }
 
   AddKnownFunctionAttributesForReplaceableGlobalAllocationFunction(FD);