[Bug target/100041] ICE in curr_insn_transform, at lra-constraints.c:4022

["marxin at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100041

--- Comment #14 from Martin Liška <marxin at gcc dot gnu.org> ---
Reduced test-case:

$ cat itanium.ii
template <typename _Tp> _Tp forward();
void snprintf(...);
struct StringView {
  StringView(char *);
};
struct Trans_NS_itanium_demangle_Node {
  enum Kind {};
  Trans_NS_itanium_demangle_Node(Kind);
};
struct FloatLiteralImpl : Trans_NS_itanium_demangle_Node {
  StringView Contents;
  Kind KindForClass;
  FloatLiteralImpl(StringView Contents_)
      : Trans_NS_itanium_demangle_Node(KindForClass), Contents(Contents_) {
    union {
      long double value;
    };
    snprintf(value);
  }
};
template <typename> struct ManglingParser;
class CanonicalizerAllocator;
template <typename, typename Alloc> struct AbstractManglingParser {
  char First;
  Alloc ASTAllocator;
  ManglingParser<CanonicalizerAllocator> getDerived();
  template <class... Args> void make(Args...) {
    ASTAllocator.template makeNode<int>(forward<Args>()...);
  }
  template <class> Trans_NS_itanium_demangle_Node *parseFloatingLiteral();
  Trans_NS_itanium_demangle_Node *parse();
};
template <typename Alloc, typename Derived>
template <class>
Trans_NS_itanium_demangle_Node *
AbstractManglingParser<Alloc, Derived>::parseFloatingLiteral() {
  StringView Data(&First);
  make(Data);
  return 0;
}
template <typename Derived, typename Alloc>
Trans_NS_itanium_demangle_Node *
AbstractManglingParser<Derived, Alloc>::parse() {
  getDerived().template parseFloatingLiteral<double>();
  return 0;
}
template <typename Alloc>
struct ManglingParser : AbstractManglingParser<int, Alloc> {};
struct CanonicalizerAllocator {
  template <typename Args> void makeNodeSimple(Args);
  struct MakeNodeImpl {
    CanonicalizerAllocator &Self;
    template <typename... Args> void make(Args...) {
      Self.makeNodeSimple<FloatLiteralImpl>(forward<Args>()...);
    }
  };
  template <typename, typename... Args> void makeNode(Args...) {
    MakeNodeImpl{*this}.make(forward<Args>()...);
  }
};
using CanonicalizingDemangler = ManglingParser<int>;
CanonicalizingDemangler parseMaybeMangledName_Demangler;
void parseMaybeMangledName() { parseMaybeMangledName_Demangler.parse(); }