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Re: [PATCH 1/2] s/390: Implement "target" attribute.
- From: Andreas Krebbel <krebbel at linux dot vnet dot ibm dot com>
- To: gcc-patches at gcc dot gnu dot org
- Date: Mon, 9 Nov 2015 08:10:29 +0100
- Subject: Re: [PATCH 1/2] s/390: Implement "target" attribute.
- Authentication-results: sourceware.org; auth=none
- References: <20150925135941 dot GA14892 at linux dot vnet dot ibm dot com> <20150925140123 dot GB14892 at linux dot vnet dot ibm dot com> <20151016123031 dot GA7320 at linux dot vnet dot ibm dot com> <20151026101022 dot GA3159 at linux dot vnet dot ibm dot com> <56337A23 dot 2070607 at linux dot vnet dot ibm dot com> <20151031175832 dot GA16391 at linux dot vnet dot ibm dot com>
On 10/31/2015 06:58 PM, Dominik Vogt wrote:
> But what the heck is this "exact power of 2" limitation good for
> in the first place? Why is a stack size of 1, 2 or
> 36028797018963968 valid, but not 800? Shouldn't the stack size
> (and the size of the stack guard) just be multiples of the stack
> slot size?
That's because of the way we implement the stack check. We use test under mask to check for certain
bits instead of doing the full math and compare.
-Andreas-