[PATCH 0/5] OpenMP/PTX: improve correctness in SIMD regions

[Alexander Monakov]

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