================
@@ -2527,6 +2527,83 @@ bool arePotentiallyOverlappingStringLiterals(const
Pointer &LHS,
return Shorter == Longer.take_front(Shorter.size());
}
+static const MaterializeTemporaryExpr *
+getInitializerListBackingArray(const Pointer &Ptr) {
+ if (Ptr.isZero() || !Ptr.isBlockPointer() || Ptr.block()->isDynamic())
+ return nullptr;
+
+ const auto *MTE =
+ dyn_cast_or_null<MaterializeTemporaryExpr>(Ptr.getDeclDesc()->asExpr());
+ return IsInitializerListBackingArray(MTE) ? MTE : nullptr;
+}
+
+static bool getArrayIndex(const Pointer &Ptr, Pointer &Array, uint64_t &Index)
{
+ if (Ptr.isZero() || !Ptr.isBlockPointer() || !Ptr.isArrayElement())
+ return false;
+
+ Pointer Expanded = Ptr.expand();
+ if (!Expanded.inArray())
+ return false;
+
+ Index = Expanded.isOnePastEnd() ? Expanded.getNumElems()
+ : static_cast<uint64_t>(Expanded.getIndex());
+ Array = Expanded.getArray();
+ return true;
+}
+
+bool arePotentiallyOverlappingInitListBackingArrays(InterpState &S,
----------------
yronglin wrote:
I have added more comments. It implements the address-comparison rejection rule
from `[intro.object]/9` (CWG2765): given two pointers that both designate
elements of `std::initializer_list` backing arrays, it returns `true` when the
two backing arrays could be merged by the implementation — i.e., their contents
agree on the overlapping region — in which case the comparison is unspecified
and must be rejected in constant evaluation. It mirrors the AST-side helper of
the same purpose in `ExprConstant.cpp`, including the conservative "missing
element data ⇒ assume potential merge" default.
https://github.com/llvm/llvm-project/pull/197458
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