Re: Drop CONSTRUCTOR comparsion from ipa-icf-gimple

[Richard Biener <richard.guenther@gmail.com>]

On Fri, Oct 16, 2015 at 5:12 AM, Jan Hubicka <hubicka@ucw.cz> wrote:
> Hi,
> as Richard noticed in my port of the code to operand_equal_p, the checking of
> CONSTURCTOR in ipa-icf-gimple is incomplete missing the index checks.
> It is also unnecesary since non-empty ctors does not happen as gimple
> operands.  This patch thus removes the unnecesary code.

Err - they do happen, for vector constructors.  Just empty constructors
are not allowed for vector constructors - vector constructors are required
to have elements in proper order and none left out.

Sorry for misleading you.

> Bootstrapped/regtested x86_64-linux, comitted.

this will definitely ICE ...

Richard.

> Honza
>
>         * ipa-icf-gimple.c (func_checker::compare_operand): Compare only
>         empty constructors.
> Index: ipa-icf-gimple.c
> ===================================================================
> --- ipa-icf-gimple.c    (revision 228851)
> +++ ipa-icf-gimple.c    (working copy)
> @@ -415,20 +415,9 @@ func_checker::compare_operand (tree t1,
>    switch (TREE_CODE (t1))
>      {
>      case CONSTRUCTOR:
> -      {
> -       unsigned length1 = vec_safe_length (CONSTRUCTOR_ELTS (t1));
> -       unsigned length2 = vec_safe_length (CONSTRUCTOR_ELTS (t2));
> -
> -       if (length1 != length2)
> -         return return_false ();
> -
> -       for (unsigned i = 0; i < length1; i++)
> -         if (!compare_operand (CONSTRUCTOR_ELT (t1, i)->value,
> -                               CONSTRUCTOR_ELT (t2, i)->value))
> -           return return_false();
> -
> -       return true;
> -      }
> +      gcc_assert (!vec_safe_length (CONSTRUCTOR_ELTS (t1))
> +                 && !vec_safe_length (CONSTRUCTOR_ELTS (t2)));
> +      return true;
>      case ARRAY_REF:
>      case ARRAY_RANGE_REF:
>        /* First argument is the array, second is the index.  */