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Re: [PATCH] Make basic asm implicitly clobber memory, pr24414
- From: Bernd Schmidt <bschmidt at redhat dot com>
- To: Bernd Edlinger <bernd dot edlinger at hotmail dot de>, "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
- Cc: Richard Biener <rguenther at suse dot de>, Jeff Law <law at redhat dot com>
- Date: Wed, 9 Dec 2015 12:06:15 +0100
- Subject: Re: [PATCH] Make basic asm implicitly clobber memory, pr24414
- Authentication-results: sourceware.org; auth=none
- References: <VI1PR07MB09116C40BE502A341AE0CB9EE4E80 at VI1PR07MB0911 dot eurprd07 dot prod dot outlook dot com>
On 12/09/2015 03:18 AM, Bernd Edlinger wrote:
Furthermore there is a documented use for asm(""): The empty assembler string is used to make a function
volatile, thus calls can not be optimized away. But I think it is not necessary to make this clobber anything,
nor should it be an instruction scheduling barrier, as it used to be in the past.
Making that change seems risky; best not to make assumptions about how
these are used. In any case,
... or should I wait for the next stage1?
I think that would be better.
Bernd