[clang] 8d908b8 - [clang][Interp] Ignore unnamed bitfields when zeroing records (#102749)

[via cfe-commits]

Author: Timm Baeder
Date: 2024-08-10T15:56:19+02:00
New Revision: 8d908b8cc5f4b3aeb2303437a9c2d35654279fd9

URL: https://github.com/llvm/llvm-project/commit/8d908b8cc5f4b3aeb2303437a9c2d35654279fd9
DIFF: https://github.com/llvm/llvm-project/commit/8d908b8cc5f4b3aeb2303437a9c2d35654279fd9.diff

LOG: [clang][Interp] Ignore unnamed bitfields when zeroing records (#102749)

Including unions, where this is more important.

Added: 
    

Modified: 
    clang/lib/AST/Interp/Compiler.cpp
    clang/test/AST/Interp/unions.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/AST/Interp/Compiler.cpp b/clang/lib/AST/Interp/Compiler.cpp
index 6c4d607706c6b..1fa7a944448fb 100644
--- a/clang/lib/AST/Interp/Compiler.cpp
+++ b/clang/lib/AST/Interp/Compiler.cpp
@@ -3356,6 +3356,9 @@ bool Compiler<Emitter>::visitZeroRecordInitializer(const Record *R,
   assert(R);
   // Fields
   for (const Record::Field &Field : R->fields()) {
+    if (Field.Decl->isUnnamedBitField())
+      continue;
+
     const Descriptor *D = Field.Desc;
     if (D->isPrimitive()) {
       QualType QT = D->getType();

diff  --git a/clang/test/AST/Interp/unions.cpp b/clang/test/AST/Interp/unions.cpp
index 6f6bc3d6891b4..1f52950b1e09b 100644
--- a/clang/test/AST/Interp/unions.cpp
+++ b/clang/test/AST/Interp/unions.cpp
@@ -297,5 +297,13 @@ namespace Zeroing {
   static_assert(u6.a[4] == 0, "");
   static_assert(u6.b == 0, ""); // both-error {{not an integral constant expression}} \
                                 // both-note {{read of member 'b' of union with active member 'a'}}
+
+  union UnionWithUnnamedBitfield {
+    int : 3;
+    int n;
+  };
+  static_assert(UnionWithUnnamedBitfield().n == 0, "");
+  static_assert(UnionWithUnnamedBitfield{}.n == 0, "");
+  static_assert(UnionWithUnnamedBitfield{1}.n == 1, "");
 }
 #endif