[libcxx-commits] [clang] [libcxx] [Clang] Normalize constraints before checking for satisfaction (PR #161671)

[Younan Zhang via libcxx-commits]

================
@@ -1960,38 +2557,47 @@ FormulaType SubsumptionChecker::Normalize(const NormalizedConstraint &NC) {
     AddUniqueClauseToFormula(Res, std::move(C));
   };
 
-  if (NC.isAtomic())
-    return {{find(NC.getAtomicConstraint())}};
+  switch (NC.getKind()) {
 
-  if (NC.isFoldExpanded())
-    return {{find(NC.getFoldExpandedConstraint())}};
+  case NormalizedConstraint::ConstraintKind::Atomic:
+    return {{find(&static_cast<const AtomicConstraint &>(NC))}};
 
-  FormulaType Left, Right;
-  SemaRef.runWithSufficientStackSpace(SourceLocation(), [&] {
-    Left = Normalize<FormulaType>(NC.getLHS());
-    Right = Normalize<FormulaType>(NC.getRHS());
-  });
+  case NormalizedConstraint::ConstraintKind::FoldExpanded:
+    return {{find(&static_cast<const FoldExpandedConstraint &>(NC))}};
 
-  if (NC.getCompoundKind() == FormulaType::Kind) {
-    auto SizeLeft = Left.size();
-    Res = std::move(Left);
-    Res.reserve(SizeLeft + Right.size());
-    std::for_each(std::make_move_iterator(Right.begin()),
-                  std::make_move_iterator(Right.end()), Add);
-    return Res;
-  }
+  case NormalizedConstraint::ConstraintKind::ConceptId:
+    return Normalize<FormulaType>(
+        static_cast<const ConceptIdConstraint &>(NC).getNormalizedConstraint());
+
+  case NormalizedConstraint::ConstraintKind::Compound: {
+    const auto &Compound = static_cast<const CompoundConstraint &>(NC);
+    FormulaType Left, Right;
+    SemaRef.runWithSufficientStackSpace(SourceLocation(), [&] {
+      Left = Normalize<FormulaType>(Compound.getLHS());
+      Right = Normalize<FormulaType>(Compound.getRHS());
+    });
+
+    if (Compound.getCompoundKind() == FormulaType::Kind) {
+      Res = std::move(Left);
+      Res.reserve(Left.size() + Right.size());
----------------
zyn0217 wrote:

> This is use after move which is undefined behavior, please fix.

Thanks for spotting that, here is the PR https://github.com/llvm/llvm-project/pull/164781

https://github.com/llvm/llvm-project/pull/161671