We've had a FINISHME here since Eric originally wrote the code in 2011.
This patch implements his suggested approach, which makes us actually
able to copy propagate into the loops, at the unfortunate cost of making
this pass even more expensive.
The shader-db statistics are basically a wash:
No change in instruction counts.
total cycles in shared programs: 78685980 -> 78680730 (-0.01%)
cycles in affected programs: 2102646 -> 2097396 (-0.25%)
helped: 48
HURT: 83
I figured if we're going to do this for one copy propagation pass,
we may as well do it in both.
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Matt Turner <mattst88@gmail.com>
This is kind of a hack. We currently track precise requirements
by decorating ir_variables. Propagating or grafting the RHS of an
assignment to a precise value into some other expression tree can
lose those decorations.
In the long run, it might be better to replace these ir_variable
decorations with an "exact" decoration on ir_expression nodes,
similar to what NIR does.
In the short run, this is probably good enough. It preserves
enough information for glsl_to_nir to generate "exact" decorations,
and NIR will then handle optimizing these expressions reasonably.
Fixes ES31-CTS.gpu_shader5.precise_qualifier.
v2: Drop invariant handling, as it shouldn't be necessary (caught
by Jason Ekstrand).
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
