[Mesa-dev] [PATCH 0/6] RadeonSI: Let's just stop spilling SGPRs

[Marek Olšák]

This is quite easy because we just have to get rid of all of
the preloading at the beginning of shaders.

I also removed preloading of PS inputs with literal indexing, which
has almost the same effect as sinking interp instructions.

I'm slightly concerned that LICM won't move interps because they are
not considered speculatively-executable (=movable) by LLVM, but
the shader-db stats show that it doesn't matter.

LLVM is smart enough to do CSE where needed for both descriptor loads
and interps. In fact, it's the CSE which is responsible for some of
the remaining SGPR spills. (It makes sense if you think about it)

The compile time increased by 6% because CSE has a lot more work,
but it's certainly worth it.


shader-db stats:

[PATCH 4/6] radeonsi: get rid of img/buf/sampler descriptor
    https://people.freedesktop.org/~mareko/no_preload1.html
[PATCH 5/6] radeonsi: get rid of constant buffer preloading
    https://people.freedesktop.org/~mareko/no_preload2.html
[PATCH 6/6] radeonsi: reload PS inputs with direct indexing at each
    https://people.freedesktop.org/~mareko/no_preload3_ps.html

Total diff:
    https://people.freedesktop.org/~mareko/no_preload_total.html

Please review.

Marek