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Re: [RFD] Extremely large alignment of read-only strings


On Wed, 27 Jul 2016, Thorsten Glaser wrote:

First of all, I think option -malign-data=abi (new in GCC 5) addresses your
need: it can be used to reduce the default (excessive) alignment to just the
psABI-dictated value (you can play with this at https://gcc.godbolt.org even if
you can't install GCC-5 locally).

Note that like with other ABI-affecting options you need to consider
implications for linking with code you're not building yourself: if the other
code expects bigger alignment, you'll have a bug.

One comment to your email below.

> After some (well, lots) more debugging, I eventually
> discovered -fdump-translation-unit (which, in the version
> I was using, also worked for C, not just C++), which showed
> me that the alignment was 256 even (only later reduced to
> 32 as that’s the maximum alignment for i386).

Most likely the quoted figures from GCC dumps are in bits, not bytes.

HTH
Alexander

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