================
@@ -851,72 +850,61 @@ void CIRRecordLowering::lowerUnion(bool
nonVirtualBaseType) {
fieldType = getStorageType(field);
}
- // This maps a field to its index. For unions, the index is always 0.
fieldIdxMap[field->getCanonicalDecl()] = 0;
+ fieldTypes.push_back(fieldType);
+ }
- // Compute zero-initializable status.
- // This union might not be zero initialized: it may contain a pointer to
- // data member which might have some exotic initialization sequence.
- // If this is the case, then we ought not to try and come up with a
"better"
- // type, it might not be very easy to come up with a Constant which
- // correctly initializes it.
- if (!seenNamedMember) {
- seenNamedMember = field->getIdentifier();
- if (!seenNamedMember)
- if (const RecordDecl *fieldRD = field->getType()->getAsRecordDecl())
- seenNamedMember = fieldRD->findFirstNamedDataMember();
- if (seenNamedMember && !isZeroInitializable(field)) {
- zeroInitializable = zeroInitializableAsBase = false;
- storageType = fieldType;
- }
- }
+ // Compute zero-initializable status.
+ // This union might not be zero initialized: it may contain a pointer to
+ // data member which might have some exotic initialization sequence.
+ // Unlike classic codegen, we don't really 'give up' on adding all the
fields,
+ // though this is a decision/implementation we might want to revisit. We
just
+ // fall back on the typical storage type calculation rather than this bizarre
+ // "choose the first thing", as that likely won't be compatible with later
+ // decisions.
+ for (const FieldDecl *field : recordDecl->fields()) {
- // Because our union isn't zero initializable, we won't be getting a better
- // storage type.
- if (!zeroInitializable)
- continue;
+ auto hasNamedMember = [](const FieldDecl *curField) -> bool {
----------------
erichkeane wrote:
Ah, hmm... I think you're right there. This DOES result in some stuff no
longer being zero-init since I am checking each field. And yeah, you're right,
i don't think I have a test that validates that.
I actually wonder if the right answer is "Zero-initializable if ANY field is"
or "Zero-init if the storage type" is? WDYT? The latter is a touch
unfortunate, since our 'storage type' is determined after the fields are
removed, and we previously decided it based on AST zero-init rules.
Anything we do here is going to be only vaguely related to the previous answers
unfortunately.
I'll have to think about this further.
https://github.com/llvm/llvm-project/pull/210709
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