[C++ PATCH] Fix up genericization ICE (PR c++/71941)

[Jason Merrill]

OK.

On Wed, Jul 20, 2016 at 5:05 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> Hi!
>
> In PR69315, we've recently allowed recursive genericization, unfortunately
> the bc_label handling isn't prepared for that, we ICE if we cp_genericize
> some function (usually newly instantiated method) while inside of some loop
> in the outer function.
>
> Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
> trunk/6.2?
>
> 2016-07-20  Jakub Jelinek  <jakub@redhat.com>
>
>         PR c++/71941
>         * cp-gimplify.c (cp_genericize): For nested cp_genericize calls
>         save/restore bc_label array.
>
>         * g++.dg/gomp/pr71941.C: New test.
>
> --- gcc/cp/cp-gimplify.c.jj     2016-07-18 20:44:59.000000000 +0200
> +++ gcc/cp/cp-gimplify.c        2016-07-20 12:14:28.203381211 +0200
> @@ -1632,6 +1632,13 @@ cp_genericize (tree fndecl)
>    if (DECL_CLONED_FUNCTION_P (fndecl))
>      return;
>
> +  /* Allow cp_genericize calls to be nested.  */
> +  tree save_bc_label[2];
> +  save_bc_label[bc_break] = bc_label[bc_break];
> +  save_bc_label[bc_continue] = bc_label[bc_continue];
> +  bc_label[bc_break] = NULL_TREE;
> +  bc_label[bc_continue] = NULL_TREE;
> +
>    /* Expand all the array notations here.  */
>    if (flag_cilkplus
>        && contains_array_notation_expr (DECL_SAVED_TREE (fndecl)))
> @@ -1651,6 +1658,8 @@ cp_genericize (tree fndecl)
>
>    gcc_assert (bc_label[bc_break] == NULL);
>    gcc_assert (bc_label[bc_continue] == NULL);
> +  bc_label[bc_break] = save_bc_label[bc_break];
> +  bc_label[bc_continue] = save_bc_label[bc_continue];
>  }
>
>  /* Build code to apply FN to each member of ARG1 and ARG2.  FN may be
> --- gcc/testsuite/g++.dg/gomp/pr71941.C.jj      2016-07-20 12:11:29.793638764 +0200
> +++ gcc/testsuite/g++.dg/gomp/pr71941.C 2016-07-20 12:11:14.000000000 +0200
> @@ -0,0 +1,22 @@
> +// PR c++/71941
> +// { dg-do compile }
> +// { dg-options "-fopenmp" }
> +
> +struct A { A (); A (A &); ~A (); };
> +
> +template <int N>
> +struct B
> +{
> +  struct C { A a; C () : a () {} };
> +  C c;
> +  void foo ();
> +};
> +
> +void
> +bar ()
> +{
> +  B<0> b;
> +#pragma omp task
> +  for (int i = 0; i < 2; i++)
> +    b.foo ();
> +}
>
>         Jakub