[cfe-dev] [llvm-dev] Disable memset synthesis

[John McCall via cfe-dev]

> On Aug 17, 2017, at 4:09 PM, Joerg Sonnenberger via cfe-dev <cfe-dev at lists.llvm.org> wrote:
> On Thu, Aug 17, 2017 at 05:56:03PM +0000, Nemanja Ivanovic via llvm-dev wrote:
>> My concern wasn't a phylosophical one but a pragmatic one. Learning about
>> poor choices when lowering memset is probably quite useful. Having a flag
>> that just turns off idiom recognition for it may just work around the
>> problem. But the problem may still exist.
> 
> Since we are talking about the frontend, it is not even Loop Idiom
> Recogniation, but the much simpler initialisation of larger variables.

Oh, I missed that.  I have no intention of changing IRGen to hand-roll
zero-initialization loops as a performance workaround.  That's not really even
disabling an optimization, that's literally asking us to add more code to IRGen
to work around a backend problem.  No way.

John.