On Mon, Apr 24, 2017 at 11:34 AM, Richard Biener
<richard.guent...@gmail.com> wrote:
> On Tue, Apr 18, 2017 at 12:41 PM, Bin Cheng <bin.ch...@arm.com> wrote:
>> Hi,
>> For now, we check validity of offset by computing the maximum offset then
>> checking if
>> offset is smaller than the max offset. This is inaccurate, for example,
>> some targets
>> may require offset to be aligned by power of 2. This patch introduces new
>> interface
>> checking validity of offset. It also buffers rtx among different calls.
>>
>> Is it OK?
>
> - static vec<HOST_WIDE_INT> max_offset_list;
> -
> + auto_vec<rtx> addr_list;
> as = TYPE_ADDR_SPACE (TREE_TYPE (use->iv->base));
> mem_mode = TYPE_MODE (TREE_TYPE (*use->op_p));
>
> - num = max_offset_list.length ();
> + num = addr_list.length ();
> list_index = (unsigned) as * MAX_MACHINE_MODE + (unsigned) mem_mode;
> if (list_index >= num)
>
> num here is always zero and thus the compare is always true.
>
> + addr_list.safe_grow_cleared (list_index + MAX_MACHINE_MODE);
> + for (; num < addr_list.length (); num++)
> + addr_list[num] = NULL;
>
> the loop is now redundant (safe_grow_cleared)
>
> + addr = addr_list[list_index];
> + if (!addr)
> {
>
> always true again...
>
> I wonder if you really indented to drop 'static' from addr_list?
> There's no caching
> across function calls.
Right, the redundancy is because I tried to cache across function
calls with declarations like:
static unsigned num = 0;
static GTY ((skip)) rtx *addr_list = NULL;
But this doesn't work, the addr_list[list_index] still gets corrupted somehow.
Thanks,
bin
>
> + /* Split group if aksed to, or the offset against the first
> + use can't fit in offset part of addressing mode. IV uses
> + having the same offset are still kept in one group. */
> + if (offset != 0 &&
> + (split_p || !addr_offset_valid_p (use, offset)))
>
> && goes to the next line.
>
> Richard.
>
>
>
>> Thanks,
>> bin
>> 2017-04-11 Bin Cheng <bin.ch...@arm.com>
>>
>> * tree-ssa-loop-ivopts.c (compute_max_addr_offset): Delete.
>> (addr_offset_valid_p): New function.
>> (split_address_groups): Check offset validity with above function.
