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Re: [trunk][patch] don't use SAVE_EXPR on TYPE_SIZE
On Tue, Jun 10, 2008 at 5:29 PM, Rafael Espindola <espindola@google.com> wrote:
>> Well, the SAVE_EXPR is to make sure side-effects in TYPE_SIZE{_UNIT}
>> are only executed once. Why is the SAVE_EXPR a problem for LTO?
>
> We don't really need a SAVE_EXPR in the IL. It can be expanded into
> two statements. We can add support for it, but it would be better to
> expand it before getting into the streamer.
>
> Another option is doing just that on build_new. I could create a temp
> variable with the size and put that on the type.
Note that after gimplification (LTO streaming is after that, right?) the
TYPE_SIZE{_UNIT}s that are still used/needed are gimplified into the
IL (and a gimple temporary is stored in the TYPE_SIZE{_UNIT}s place)
and the SAVE_EXPRs are removed. So if after gimplification
!is_gimple_val trees in TYPE_SIZE{_UNIT} remain they are "unused".
Of course not (de-)serializing them at all might still break stuff.
Richard.