On Tue, Oct 1, 2013 at 10:31 AM, Cong Hou <[email protected]> wrote:
> The current uniform_vector_p() function only returns non-NULL when the
> vector is directly a uniform vector. For example, for the following
> gimple code:
>
> vect_cst_.15_91 = {_9, _9, _9, _9, _9, _9, _9, _9};
>
>
> The current implementation can only detect that {_9, _9, _9, _9, _9,
> _9, _9, _9} is a uniform vector, but fails to recognize
> vect_cst_.15_91 is also one. This simple patch searches through
> assignment chains to find more uniform vectors.
>
>
> thanks,
> Cong
>
>
>
> diff --git a/gcc/ChangeLog b/gcc/ChangeLog
> index 45c1667..b42f8a9 100644
> --- a/gcc/ChangeLog
> +++ b/gcc/ChangeLog
> @@ -1,3 +1,9 @@
> +2013-10-01 Cong Hou <[email protected]>
> +
> + * tree.c: Improve the function uniform_vector_p() so that a
> + vector assigned with a uniform vector is also treated as a
> + uniform vector.
> +
> diff --git a/gcc/tree.c b/gcc/tree.c
> index 1c881e4..1d6d894 100644
> --- a/gcc/tree.c
> +++ b/gcc/tree.c
> @@ -10297,6 +10297,17 @@ uniform_vector_p (const_tree vec)
> return first;
> }
>
> + if (TREE_CODE (vec) == SSA_NAME)
> + {
> + gimple def = SSA_NAME_DEF_STMT (vec);
> + if (gimple_code (def) == GIMPLE_ASSIGN)
do this:
if (is_gimple_assign (def) && gimple_assign_copy_p (def))
> + {
> + tree rhs = gimple_op (def, 1);
> + if (VECTOR_TYPE_P (TREE_TYPE (rhs)))
> + return uniform_vector_p (rhs);
> + }
> + }
> +
> return NULL_TREE;
> }
Do you have a test case showing what missed optimization this fix can enable ?
David
