On Tue, Oct 1, 2013 at 2:37 PM, Xinliang David Li <[email protected]> wrote:
> 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))
Wrong comment from me. Should be
if (gimple_assign_single_p (def))
..
David
>
>> + {
>> + 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
