shafik updated this revision to Diff 512983.
shafik added a comment.
- Added codegen test
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D146329/new/
https://reviews.llvm.org/D146329
Files:
clang/lib/Sema/SemaDeclCXX.cpp
clang/test/CXX/class/class.compare/class.compare.default/p1.cpp
clang/test/CodeGenCXX/defaulted_equality_ignore_unnamed_bitfields.cpp
Index: clang/test/CodeGenCXX/defaulted_equality_ignore_unnamed_bitfields.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGenCXX/defaulted_equality_ignore_unnamed_bitfields.cpp
@@ -0,0 +1,27 @@
+// RUN: %clang_cc1 %s -triple x86_64-linux -emit-llvm -o - | FileCheck %s
+
+// Check that we don't attempt to compare the unnamed bitfields
+struct A {
+ unsigned x : 1;
+ unsigned : 1;
+
+ friend bool operator==(A, A);
+};
+
+
+struct B {
+ unsigned x : 1;
+ unsigned : 31;
+
+ friend bool operator==(B, B);
+};
+
+bool operator==(A, A) = default;
+bool operator==(B, B) = default;
+
+
+// If it compares the unnamed bitfields it will first compare the named
bit-field
+// and then branch based on the result of that comparison.
+// We also won't see a lshr in order to clear the named bitfield.
+// CHECK-NOT: br
+// CHECK-NOT: lshr
Index: clang/test/CXX/class/class.compare/class.compare.default/p1.cpp
===================================================================
--- clang/test/CXX/class/class.compare/class.compare.default/p1.cpp
+++ clang/test/CXX/class/class.compare/class.compare.default/p1.cpp
@@ -226,3 +226,26 @@
(void)(b == 0);
}
} // namespace p2085_2
+
+namespace GH61417 {
+struct A {
+ unsigned x : 1;
+ unsigned : 0;
+ unsigned y : 1;
+
+ constexpr A() : x(0), y(0) {}
+ bool operator==(const A& rhs) const noexcept = default;
+};
+
+void f1() {
+ constexpr A a, b;
+ constexpr bool c = (a == b); // no diagnostic, we should not be comparing the
+ // unnamed bit-field which is indeterminate
+}
+
+void f2() {
+ A a, b;
+ bool c = (a == b); // no diagnostic nor crash during codegen attempting to
+ // access info for unnamed bit-field
+}
+}
Index: clang/lib/Sema/SemaDeclCXX.cpp
===================================================================
--- clang/lib/Sema/SemaDeclCXX.cpp
+++ clang/lib/Sema/SemaDeclCXX.cpp
@@ -7755,6 +7755,10 @@
// followed by the non-static data members of C
for (FieldDecl *Field : Record->fields()) {
+ // C++23 [class.bit]p2:
+ // Unnamed bit-fields are not members ...
+ if (Field->isUnnamedBitfield())
+ continue;
// Recursively expand anonymous structs.
if (Field->isAnonymousStructOrUnion()) {
if (visitSubobjects(Results, Field->getType()->getAsCXXRecordDecl(),
Index: clang/test/CodeGenCXX/defaulted_equality_ignore_unnamed_bitfields.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGenCXX/defaulted_equality_ignore_unnamed_bitfields.cpp
@@ -0,0 +1,27 @@
+// RUN: %clang_cc1 %s -triple x86_64-linux -emit-llvm -o - | FileCheck %s
+
+// Check that we don't attempt to compare the unnamed bitfields
+struct A {
+ unsigned x : 1;
+ unsigned : 1;
+
+ friend bool operator==(A, A);
+};
+
+
+struct B {
+ unsigned x : 1;
+ unsigned : 31;
+
+ friend bool operator==(B, B);
+};
+
+bool operator==(A, A) = default;
+bool operator==(B, B) = default;
+
+
+// If it compares the unnamed bitfields it will first compare the named bit-field
+// and then branch based on the result of that comparison.
+// We also won't see a lshr in order to clear the named bitfield.
+// CHECK-NOT: br
+// CHECK-NOT: lshr
Index: clang/test/CXX/class/class.compare/class.compare.default/p1.cpp
===================================================================
--- clang/test/CXX/class/class.compare/class.compare.default/p1.cpp
+++ clang/test/CXX/class/class.compare/class.compare.default/p1.cpp
@@ -226,3 +226,26 @@
(void)(b == 0);
}
} // namespace p2085_2
+
+namespace GH61417 {
+struct A {
+ unsigned x : 1;
+ unsigned : 0;
+ unsigned y : 1;
+
+ constexpr A() : x(0), y(0) {}
+ bool operator==(const A& rhs) const noexcept = default;
+};
+
+void f1() {
+ constexpr A a, b;
+ constexpr bool c = (a == b); // no diagnostic, we should not be comparing the
+ // unnamed bit-field which is indeterminate
+}
+
+void f2() {
+ A a, b;
+ bool c = (a == b); // no diagnostic nor crash during codegen attempting to
+ // access info for unnamed bit-field
+}
+}
Index: clang/lib/Sema/SemaDeclCXX.cpp
===================================================================
--- clang/lib/Sema/SemaDeclCXX.cpp
+++ clang/lib/Sema/SemaDeclCXX.cpp
@@ -7755,6 +7755,10 @@
// followed by the non-static data members of C
for (FieldDecl *Field : Record->fields()) {
+ // C++23 [class.bit]p2:
+ // Unnamed bit-fields are not members ...
+ if (Field->isUnnamedBitfield())
+ continue;
// Recursively expand anonymous structs.
if (Field->isAnonymousStructOrUnion()) {
if (visitSubobjects(Results, Field->getType()->getAsCXXRecordDecl(),
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