On Thu, Sep 12, 2019 at 1:28 AM Gary Oblock <gobl...@marvell.com> wrote: > > I'm trying to do a set of optimizations that drastically transform the > layout of arrays of structures. For obvious reasons they will need to > run at LTO time. I'm running into some difficulties comprehending how > the initialization data is stored. Also, I'm seeing DECL_INITIALs > being set to NULL and that is worrisome since it would throw a monkey > wrench into what I'm doing. That is, because for my optimizations to > work they will need to either disqualify an array with initialization > data or transform said data. > > So, is the initialization data being hidden at LTO time? > If not what's its format and how do I best manipulate it?
You probably have to do at least part of the work at WPA time where DECL_INITIAL should be appropriately set. Initializers are generally only shipped to / output in one LTRANS unit unless they can be used for constant folding. > Any insight into how to deal with these problem would be most helpful. > These are some really interesting optimizations and will greatly speed > up code that uses large arrays of structures. Usually hinting the programmer is way easier here since a compiler has to give up too easily for data layout optimizations. Unless you only target specific benchmarks... Richard. > > Thanks, > > Gary Oblock
