[clang] [clang] assume_aligned incorrectly diagnoses a dependent return type (PR #111573)

[Amr Hesham via cfe-commits]

https://github.com/AmrDeveloper updated https://github.com/llvm/llvm-project/pull/111573

>From 4202153623dd64cec76b6ca9a08191ff884327a7 Mon Sep 17 00:00:00 2001
From: AmrDeveloper <amr96 at programmer.net>
Date: Tue, 8 Oct 2024 20:12:45 +0200
Subject: [PATCH] [clang] assume_aligned incorrectly diagnoses a dependent
 return type

---
 clang/include/clang/Sema/Sema.h                    | 6 +++---
 clang/lib/Sema/SemaDeclAttr.cpp                    | 7 ++++---
 clang/test/SemaCXX/builtin-assume-aligned-tmpl.cpp | 3 +++
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index 7ff9c2754a6fe0..19e9392d2d5352 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -4453,9 +4453,9 @@ class Sema final : public SemaBase {
                                       SourceLocation *ArgLocation = nullptr);
 
   /// Determine if type T is a valid subject for a nonnull and similar
-  /// attributes. By default, we look through references (the behavior used by
-  /// nonnull), but if the second parameter is true, then we treat a reference
-  /// type as valid.
+  /// attributes. By default, we skip dependence and look through references
+  /// (the behavior used by nonnull), but if the second parameter is true, then
+  /// we treat a reference type as valid.
   bool isValidPointerAttrType(QualType T, bool RefOkay = false);
 
   /// AddAssumeAlignedAttr - Adds an assume_aligned attribute to a particular
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index af983349a89b58..e2174ba926f17f 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -1216,6 +1216,8 @@ static void handlePreferredName(Sema &S, Decl *D, const ParsedAttr &AL) {
 }
 
 bool Sema::isValidPointerAttrType(QualType T, bool RefOkay) {
+  if (T->isDependentType())
+    return true;
   if (RefOkay) {
     if (T->isReferenceType())
       return true;
@@ -1284,7 +1286,7 @@ static void handleNonNullAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
     for (unsigned I = 0, E = getFunctionOrMethodNumParams(D);
          I != E && !AnyPointers; ++I) {
       QualType T = getFunctionOrMethodParamType(D, I);
-      if (T->isDependentType() || S.isValidPointerAttrType(T))
+      if (S.isValidPointerAttrType(T))
         AnyPointers = true;
     }
 
@@ -1409,8 +1411,7 @@ void Sema::AddAllocAlignAttr(Decl *D, const AttributeCommonInfo &CI,
   AllocAlignAttr TmpAttr(Context, CI, ParamIdx());
   SourceLocation AttrLoc = CI.getLoc();
 
-  if (!ResultType->isDependentType() &&
-      !isValidPointerAttrType(ResultType, /* RefOkay */ true)) {
+  if (!isValidPointerAttrType(ResultType, /* RefOkay */ true)) {
     Diag(AttrLoc, diag::warn_attribute_return_pointers_refs_only)
         << &TmpAttr << CI.getRange() << getFunctionOrMethodResultSourceRange(D);
     return;
diff --git a/clang/test/SemaCXX/builtin-assume-aligned-tmpl.cpp b/clang/test/SemaCXX/builtin-assume-aligned-tmpl.cpp
index 61b85557d6b294..4459580cdccc5d 100644
--- a/clang/test/SemaCXX/builtin-assume-aligned-tmpl.cpp
+++ b/clang/test/SemaCXX/builtin-assume-aligned-tmpl.cpp
@@ -52,6 +52,9 @@ T *atest3() __attribute__((assume_aligned(31, o))); // expected-error {{requeste
 template <typename T, int o>
 T *atest4() __attribute__((assume_aligned(32, o)));
 
+template<typename T>
+T atest5(int) __attribute__((assume_aligned(2)));
+
 void test22() {
   atest3<int, 5>();
   atest4<int, 5>();