nir: Add a discard optimization pass
This is a rebased version of !2339 with the Intel change dropped and radeonsi code added.
No piglit/deqp regression.
shaderdb:
| Master vs MR | Shaders | SGPRs | VGPRs | SpillSGPR | CodeSize | MaxWaves |
|---|---|---|---|---|---|---|
| All affected | 2082 | 1.92 % | -2.67 % | -100.00 % | 0.13 % | 2.43 % |
| Total | 54433 | 0.08 % | -0.11 % | -0.23 % | . | 0.09 % |
with glsl_correct_derivatives_after_discard=true:
| Master vs MR | Shaders | SGPRs | VGPRs | SpillSGPR | CodeSize | MaxWaves |
|---|---|---|---|---|---|---|
| All affected | 5510 | -1.63 % | -1.04 % | -9.67 % | 0.10 % | 0.96 % |
| Total | 54433 | -0.19 % | -0.12 % | -1.75 % | 0.01 % | 0.09 % |
Edited by Pierre-Eric Pelloux-Prayer