[clang] e5bbc9f - [Clang] Fixes __builtin_is_implicit_lifetime for types with deleted ctrs (#161163)

[via cfe-commits]

Author: Corentin Jabot
Date: 2025-09-29T15:55:35+02:00
New Revision: e5bbc9feae3c6b7f377f89abae47fc3819c73f95

URL: https://github.com/llvm/llvm-project/commit/e5bbc9feae3c6b7f377f89abae47fc3819c73f95
DIFF: https://github.com/llvm/llvm-project/commit/e5bbc9feae3c6b7f377f89abae47fc3819c73f95.diff

LOG: [Clang] Fixes __builtin_is_implicit_lifetime for types with deleted ctrs (#161163)

We failed to check that the trivial constructor where eligible (this
implies non deleted).

Fixes #160610

Added: 
    

Modified: 
    clang/docs/ReleaseNotes.rst
    clang/lib/Sema/SemaTypeTraits.cpp
    clang/test/SemaCXX/type-traits.cpp

Removed: 
    


################################################################################
diff  --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 270b5d336eba7..e8deae50e4cb0 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -432,6 +432,7 @@ Bug Fixes to C++ Support
 - Fix an assertion failure when taking the address on a non-type template parameter argument of
   object type. (#GH151531)
 - Suppress ``-Wdouble-promotion`` when explicitly asked for with C++ list initialization (#GH33409).
+- Fix the result of `__builtin_is_implicit_lifetime` for types with a user-provided constructor. (#GH160610)
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^

diff  --git a/clang/lib/Sema/SemaTypeTraits.cpp b/clang/lib/Sema/SemaTypeTraits.cpp
index c2427dcf52538..6c798d6acb0a0 100644
--- a/clang/lib/Sema/SemaTypeTraits.cpp
+++ b/clang/lib/Sema/SemaTypeTraits.cpp
@@ -1163,13 +1163,16 @@ static bool EvaluateUnaryTypeTrait(Sema &Self, TypeTrait UTT,
     //   - it has at least one trivial eligible constructor and a trivial,
     //     non-deleted destructor.
     const CXXDestructorDecl *Dtor = RD->getDestructor();
-    if (UnqualT->isAggregateType())
-      if (Dtor && !Dtor->isUserProvided())
-        return true;
-    if (RD->hasTrivialDestructor() && (!Dtor || !Dtor->isDeleted()))
-      if (RD->hasTrivialDefaultConstructor() ||
-          RD->hasTrivialCopyConstructor() || RD->hasTrivialMoveConstructor())
-        return true;
+    if (UnqualT->isAggregateType() && (!Dtor || !Dtor->isUserProvided()))
+      return true;
+    if (RD->hasTrivialDestructor() && (!Dtor || !Dtor->isDeleted())) {
+      for (CXXConstructorDecl *Ctr : RD->ctors()) {
+        if (Ctr->isIneligibleOrNotSelected() || Ctr->isDeleted())
+          continue;
+        if (Ctr->isTrivial())
+          return true;
+      }
+    }
     return false;
   }
   case UTT_IsIntangibleType:

diff  --git a/clang/test/SemaCXX/type-traits.cpp b/clang/test/SemaCXX/type-traits.cpp
index 3f0124755c674..d49330f97fad0 100644
--- a/clang/test/SemaCXX/type-traits.cpp
+++ b/clang/test/SemaCXX/type-traits.cpp
@@ -2038,6 +2038,49 @@ void is_implicit_lifetime(int n) {
   static_assert(__builtin_is_implicit_lifetime(int * __restrict));
 }
 
+namespace GH160610 {
+class NonAggregate {
+public:
+    NonAggregate() = default;
+
+    NonAggregate(const NonAggregate&)            = delete;
+    NonAggregate& operator=(const NonAggregate&) = delete;
+private:
+    int num;
+};
+
+class DataMemberInitializer {
+public:
+    DataMemberInitializer() = default;
+
+    DataMemberInitializer(const DataMemberInitializer&)            = delete;
+    DataMemberInitializer& operator=(const DataMemberInitializer&) = delete;
+private:
+    int num = 0;
+};
+
+class UserProvidedConstructor {
+public:
+    UserProvidedConstructor() {}
+
+    UserProvidedConstructor(const UserProvidedConstructor&)            = delete;
+    UserProvidedConstructor& operator=(const UserProvidedConstructor&) = delete;
+};
+
+static_assert(__builtin_is_implicit_lifetime(NonAggregate));
+static_assert(!__builtin_is_implicit_lifetime(DataMemberInitializer));
+static_assert(!__builtin_is_implicit_lifetime(UserProvidedConstructor));
+
+#if __cplusplus >= 202002L
+template <typename T>
+class Tpl {
+    Tpl() requires false = default ;
+};
+static_assert(!__builtin_is_implicit_lifetime(Tpl<int>));
+
+#endif
+}
+
 void is_signed()
 {
   //static_assert(__is_signed(char));