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Re: [PATCH i386 5/8] [AVX-512] Extend vectorizer hooks.
- From: Uros Bizjak <ubizjak at gmail dot com>
- To: Eric Botcazou <ebotcazou at adacore dot com>
- Cc: Kirill Yukhin <kirill dot yukhin at gmail dot com>, "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>, Richard Henderson <rth at redhat dot com>, Jakub Jelinek <jakub at redhat dot com>
- Date: Fri, 3 Jan 2014 12:25:00 +0100
- Subject: Re: [PATCH i386 5/8] [AVX-512] Extend vectorizer hooks.
- Authentication-results: sourceware.org; auth=none
- References: <20131112123633 dot GC34333 at msticlxl57 dot ims dot intel dot com> <201401022318 dot 15106 dot ebotcazou at adacore dot com> <CAFULd4bqaCZcJZmqZ9Cj=5vUJzofKJWg2hDxCm=-2g6yte66zQ at mail dot gmail dot com> <201401031220 dot 34808 dot ebotcazou at adacore dot com>
On Fri, Jan 3, 2014 at 12:20 PM, Eric Botcazou <ebotcazou@adacore.com> wrote:
>> When compiled with -m32 -mavx, we get:
>>
>> .align 32
>> .type a, @object
>> .size a, 32
>> a:
>>
>> so, the alignment was already raised elsewhere. We get .align 16 for
>> -msse -m32 when vectorizing.
>>
>> without -msse (and consequently without vectorizing), we get for -m32:
>>
>> .align 4
>> .type a, @object
>> .size a, 32
>> a:
>>
>> which corresponds to 32bit ABI rules (we still get .align16 for 64bit ABI).
>
> Yes, but the issue is that it was 32 before so the alignment decrease is weird.
Yes, but this change is benign, and as shown, I don't think we need
this functionality at all. The data from other TUs is accessed with a
4 byte alignment (on 32bit targets, and unfortunately also on 64bit
targets), and the alignment of local data is increased elsewhere.
I am testing a patch that removes "max_align" part from ix86_data_alignment.
Uros.