glsl: tidy up IR after loop unrolling

Graphics / Mesa 3D Graphics Library / Mesa - Timothy Arceri [itsqueeze.com] - 9 October 2017 19:05 EDT

c7affbf6875622a enabled GLSLOptimizeConservatively on some drivers. The idea was to speed up compile times by running the GLSL IR passes only once each time do_common_optimization() is called. However loop unrolling can create a big mess and with large loops can actually case compile times to increase significantly due to a bunch of redundant if statements being propagated to other IRs.

Here we make sure to clean things up before moving on.

There was no measureable difference in shader-db compile times, but it makes compile times of some piglit tests go from a couple of seconds to basically instant.

The shader-db results seemed positive also:

Totals: SGPRS: 2829456 -> 2828376 (-0.04 %)
VGPRS: 1720793 -> 1721457 (0.04 %) Spilled SGPRs: 7707 -> 7707 (0.00 %) Spilled VGPRs: 33 -> 33 (0.00 %) Private memory VGPRs: 3140 -> 2060 (-34.39 %) Scratch size: 3308 -> 2180 (-34.10 %) dwords per thread Code Size: 79441464 -> 79214616 (-0.29 %) bytes LDS: 436 -> 436 (0.00 %) blocks Max Waves: 558670 -> 558571 (-0.02 %) Wait states: 0 -> 0 (0.00 %)

7a7fb90 glsl: tidy up IR after loop unrolling
src/compiler/glsl/glsl_parser_extras.cpp | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

Upstream: cgit.freedesktop.org


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