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Re: [PATCH 1/3][AArch64][PR target/65797] Strengthen barriers for sync-fetch-op builtins.
- From: Marcus Shawcroft <marcus dot shawcroft at gmail dot com>
- To: James Greenhalgh <james dot greenhalgh at arm dot com>
- Cc: Matthew Wahab <Matthew dot Wahab at arm dot com>, gcc-patches <gcc-patches at gcc dot gnu dot org>
- Date: Mon, 1 Jun 2015 15:00:42 +0100
- Subject: Re: [PATCH 1/3][AArch64][PR target/65797] Strengthen barriers for sync-fetch-op builtins.
- Authentication-results: sourceware.org; auth=none
- References: <555E004C dot 3060704 at arm dot com> <20150526093242 dot GC23464 at arm dot com> <556C4AB0 dot 4090901 at arm dot com> <20150601121506 dot GB29884 at arm dot com>
>> Attached updated patch:
>> - Expanded the comment for aarch64_emit_post_barrier.
>> - Used 'barrier' rather than 'fence' in comments.
>> - Simplified the code for the initial load.
>>
>> Tested with check-gcc for aarch64-none-linux-gnu.
>>
>> Ok?
>> Matthew
>>
>> 2015-06-01 Matthew Wahab <matthew.wahab@arm.com>
>>
>> PR target/65697
>> * config/aarch64/aarch64.c (aarch64_split_compare_and_swap): Check
>> for __sync memory models, emit initial loads and final barriers as
>> appropriate.
>>
>
> OK,
>
> Thanks,
> James
We are emitting __sync primitives with insufficient barriers in gcc5
(and gcc4.9?) I would expect that anyone hitting this issue in
production will have a tough job debugging it. We need to look at
back porting this patch set and the prerequisite patches.... Cheers
/Marcus