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
