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Re: [PATCH 0/5] OpenMP/PTX: improve correctness in SIMD regions
On Wed, 18 Jan 2017, Jakub Jelinek wrote:
> We are talking here about addressable vars, right (so if we turn it into
> non-addressable, in the SIMT region we just use the normal PTX pseudos),
> right? We could emit inner ={v} {CLOBBER}; before SIMT_EXIT() to make it
> clear it shouldn't be moved afterwards. For the private vars used directly
> in SIMD region, for the vars from inlined functions I assume if they are
> addressable we emit clobbers for them too. Or perhaps the alias oracle can
> say that SIMT_EXIT ifn can clobber any addressable var with that
> flag/attribute. And yes, SRA would need to propagate it.
What about motion in the other direction, upwards across SIMT_ENTER()?
> But I believe it is worth it, because inlining is essential for good
> performance of the simd regions.
It is, but I think my approach is compatible with inlining too (and has a more
localized impact on the compiler).
Alexander