Re: [PATCH] Fix another ICE with C++ addressable bitsize 0 return value (PR c++/82159)

[Jason Merrill <jason at redhat dot com>]

OK.

On Wed, Oct 11, 2017 at 4:54 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> Hi!
>
> Another case where we ICE because we optimize away store to bitsize 0
> addressable object from call.  We can't optimize them away, otherwise
> we'd try to create the temporaries again and fail to do so.
>
> Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
> trunk?
>
> 2017-10-11  Jakub Jelinek  <jakub@redhat.com>
>
>         PR c++/82159
>         * expr.c (store_field): Don't optimize away bitsize == 0 store
>         from CALL_EXPR with addressable return type.
>
>         * g++.dg/opt/pr82159-2.C: New test.
>
> --- gcc/expr.c.jj       2017-10-10 22:04:06.000000000 +0200
> +++ gcc/expr.c  2017-10-11 16:48:45.428536126 +0200
> @@ -6749,8 +6749,11 @@ store_field (rtx target, HOST_WIDE_INT b
>      return const0_rtx;
>
>    /* If we have nothing to store, do nothing unless the expression has
> -     side-effects.  */
> -  if (bitsize == 0)
> +     side-effects.  Don't do that for zero sized addressable lhs of
> +     calls.  */
> +  if (bitsize == 0
> +      && (!TREE_ADDRESSABLE (TREE_TYPE (exp))
> +         || TREE_CODE (exp) != CALL_EXPR))
>      return expand_expr (exp, const0_rtx, VOIDmode, EXPAND_NORMAL);
>
>    if (GET_CODE (target) == CONCAT)
> --- gcc/testsuite/g++.dg/opt/pr82159-2.C.jj     2017-10-11 17:27:18.050861346 +0200
> +++ gcc/testsuite/g++.dg/opt/pr82159-2.C        2017-10-11 17:27:27.081753330 +0200
> @@ -0,0 +1,65 @@
> +// PR c++/82159
> +// { dg-do compile }
> +// { dg-options "" }
> +
> +template <typename T> struct D { T e; };
> +struct F : D<int[0]> {
> +  F(const F &);
> +};
> +struct G : F {
> +  template <class T> G operator-(T);
> +};
> +template <class T> struct I {
> +  typedef typename T::template J<I> ak;
> +};
> +template <class T> struct K { typename I<T>::ak an; };
> +struct H {
> +  G l;
> +};
> +struct C {
> +  ~C();
> +};
> +template <class T> struct M : T {
> +  template <typename U, typename V> M(U, V);
> +  H h;
> +  virtual void foo() { T::bar(&h); }
> +};
> +template <int, typename> class A;
> +template <class> struct B {
> +  typedef int BT;
> +  struct BC {};
> +  template <class T> struct BD {
> +    G g;
> +    BD(BT, T n) : g(n.l - 0) {}
> +  };
> +  B(BT, BC);
> +};
> +template <typename> struct O;
> +template <int T, typename U>
> +struct O<B<A<T, U> > > : public B<A<T, U> >::BC {};
> +struct L : B<A<2, double> > {
> +  struct P : C {
> +    void bar(H *x) {
> +      BT a;
> +      BD<H>(a, *x);
> +    }
> +  };
> +  template <typename U, typename V> L(U x, V n) : B(x, n) {}
> +  int ll;
> +  virtual int baz() { M<P>(this, ll); }
> +};
> +template <typename> class Q {
> +  O<B<A<2, double> > > q;
> +  virtual L baz() { L(0, q); }
> +};
> +template <template <class> class T> struct R {
> +  R() { T<int>(); }
> +};
> +struct S {
> +  template <class> class J : R<Q> {};
> +};
> +void foo() { K<S> c; }
> +
> +int main() {
> +  return 0;
> +}
>
>         Jakub