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Subject: Re: stack grow direction wrongly detected
To: cygwin@cygwin.com
References: <6eded5d3-93f3-7c98-5055-ee5ac2566bc8@gmail.com>
 <20210305233104.782838da83161a90f56a5369@nifty.ne.jp>
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From: Thomas Wolff <towo@towo.net>
Message-ID: <0162d7c3-54a4-3ecd-f6d5-b568ec1d9402@towo.net>
Date: Sat, 6 Mar 2021 10:29:01 +0100
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Am 06.03.2021 um 09:29 schrieb Marco Atzeri via Cygwin:
> On 05.03.2021 15:43, gs-cygwin.com@gluelogic.com wrote:
>> On Fri, Mar 05, 2021 at 11:31:04PM +0900, Takashi Yano via Cygwin wrote:
>>> On Fri, 5 Mar 2021 13:18:38 +0100
>>> Marco Atzeri wrote:
>>>> Hi Guys,
>>>> noted trying to rebuild guile 1.8.8.
>>>>
>>>> The following piece of code in the past
>>>> was setting SCM_I_GSC_STACK_GROWS_UP=0
>>>> and now produces SCM_I_GSC_STACK_GROWS_UP=1
>>>>
>>>> I assume some change in the gcc compiler is causing the issue.
>>>> I presume most of the programs and libraries do not care,
>>>> but some special one like guile crashes during build for this issue,
>>>> so be aware.
>>>>
>>>> Regards
>>>> Marco
>>>>
>
>>
>> If the compiler is gcc or clang:
>>
>> __attribute__(__noinline__)
>
> thanks Glenn,
>
> as
> __attribute__((__noinline__))
>
> it seems to work
> for all variant of -Ox
>
>> int
>> find_stack_direction ()
>> {
>> ...
>> }
>>
>> Cheers, Glenn
Can somebody explain the weird behaviour previously described, address 
of the char going up 1 byte a few times, then skipping down, etc, and 
why recursive calls are affected at all by inline, and what gcc thinks 
it can optimize in that case?
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