Author: rsmith
Date: Thu May 30 13:45:12 2019
New Revision: 362147
URL: http://llvm.org/viewvc/llvm-project?rev=362147&view=rev
Log:
[c++2a] Fix assertion failure if we would walk over more than one level
of derived-to-base conversion path when implicitly starting union
subobject lifetimes in constant evaluation.
Modified:
cfe/trunk/lib/AST/ExprConstant.cpp
cfe/trunk/test/SemaCXX/constant-expression-cxx2a.cpp
Modified: cfe/trunk/lib/AST/ExprConstant.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ExprConstant.cpp?rev=362147&r1=362146&r2=362147&view=diff
==============================================================================
--- cfe/trunk/lib/AST/ExprConstant.cpp (original)
+++ cfe/trunk/lib/AST/ExprConstant.cpp Thu May 30 13:45:12 2019
@@ -5031,7 +5031,8 @@ static bool HandleUnionActiveMemberChang
if (ICE->getCastKind() != CK_DerivedToBase &&
ICE->getCastKind() != CK_UncheckedDerivedToBase)
break;
- for (const CXXBaseSpecifier *Elt : ICE->path()) {
+ // Walk path backwards as we walk up from the base to the derived class.
+ for (const CXXBaseSpecifier *Elt : llvm::reverse(ICE->path())) {
--PathLength;
(void)Elt;
assert(declaresSameEntity(Elt->getType()->getAsCXXRecordDecl(),
Modified: cfe/trunk/test/SemaCXX/constant-expression-cxx2a.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/constant-expression-cxx2a.cpp?rev=362147&r1=362146&r2=362147&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/constant-expression-cxx2a.cpp (original)
+++ cfe/trunk/test/SemaCXX/constant-expression-cxx2a.cpp Thu May 30 13:45:12
2019
@@ -521,4 +521,14 @@ namespace Union {
u1 = u2;
return true;
}();
+
+ struct S1 {
+ int n;
+ };
+ struct S2 : S1 {};
+ struct S3 : S2 {};
+ void f() {
+ S3 s;
+ s.n = 0;
+ }
}
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