On February 26, 2019 6:50:13 PM GMT+01:00, "Martin Liška" <mli...@suse.cz>
wrote:
>On 2/26/19 4:02 PM, Richard Biener wrote:
>> On Tue, Feb 26, 2019 at 3:30 PM Martin Liška <mli...@suse.cz> wrote:
>>>
>>> Hi.
>>>
>>> I've rewritten bitmap memory statistics which abused unsigned
>>> type via register_overhead (map, -((int)sizeof (bitmap_head))).
>>> I come up with a concept that each bitmap has assigned a unique ID
>>> which is used for stats tracking. It's caused by fact that e.g. DF
>is
>>> heavily reallocating bitmaps that then have a different address.
>>>
>>> Survives bootstrap with --enable-gather-detailed-mem-stats.
>>>
>>> Ready for next stage1?
>>
>> + /* Get bitmap descriptor UID casted to an unsigned integer
>pointer. */
>> + unsigned *get_descriptor ()
>> + {
>> + return (unsigned *)(ptrdiff_t)alloc_descriptor;
>> + }
>>
>> this one is a bit ugly and together with
>
>I know it's not perfect.
>
>>
>> template <typename Type>
>> inline hashval_t
>> pointer_hash <Type>::hash (const value_type &candidate)
>> {
>> /* This is a really poor hash function, but it is what the current
>code uses,
>> so I am reusing it to avoid an additional axis in testing. */
>> return (hashval_t) ((intptr_t)candidate >> 3);
>>
>> will give quite some hash collisions. So I guess you should shift
>> the descriptor << 3 at least (and then make it at most 29 bits in
>> size?).
>
>That's easily doable.
>
>> Not sure what to do about the descriptor wrapping btw.
>
>Question is whether we want to invest in our internal scaffolding more
>time?
>Or can we live with the ugly casting?
I guess we can live with it if we can avoid the hash collisions.
Richard.
>Martin
>
>>
>> Richard.
>>
>>> Thanks,
>>> Martin
>>>
>>> gcc/ChangeLog:
>>>
>>> 2019-02-26 Martin Liska <mli...@suse.cz>
>>>
>>> * bitmap.c (bitmap_register): Come up with
>>> alloc_descriptor_max_uid and assign it for
>>> a new bitmap.
>>> (register_overhead): Use get_descriptor as
>>> a descriptor.
>>> (release_overhead): New.
>>> (bitmap_elem_to_freelist): Call it.
>>> (bitmap_elt_clear_from): Likewise.
>>> (bitmap_obstack_free): Likewise.
>>> (bitmap_move): Sensitively release memory.
>>> * bitmap.h (struct GTY): Add alloc_descriptor.
>>> (bitmap_initialize): Initialize alloc_descriptor to zero.
>>> * tree-ssa-pre.c (do_hoist_insertion): Use bitmap_move.
>>> ---
>>> gcc/bitmap.c | 39 ++++++++++++++++++++++++++++-----------
>>> gcc/bitmap.h | 17 ++++++++++++++---
>>> gcc/tree-ssa-pre.c | 2 +-
>>> 3 files changed, 43 insertions(+), 15 deletions(-)
>>>
>>>
