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Re: [PATCH] libio: Add small optimization on fmemopen


On 09/21/2016 11:47 AM, Florian Weimer wrote:
We don't know the nature of the GCC issue, so we cannot work around it reliably. The most likely explanation is that Address Sanitizer does not account for a valid GCC optimization.

That's not the sense that I get from looking at Bug 66661. GCC is assuming it can do an aligned word load of the trailing bytes of a flexible array member in a properly-aligned structure. This assumption is something we can easily work around reliably, e.g., with the patch I suggested. Although the followups to Bug 66661 suggest that there may be further problems with overaligned structures, the code here is not using _Alignas so these further problems are not an issue here.


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