v2:
- only allow nir_op_inot or nir_op_b2i when alu input is 1.
- use some helpers as suggested by Jason.
v3:
- evaluate alu op for single input alu ops
- add helper function to decide if to propagate through alu
- make use of nir_before_src in another spot
shader-db IVB results:
total instructions in shared programs: 9993483 -> 9993472 (-0.00%)
instructions in affected programs: 1300 -> 1289 (-0.85%)
helped: 11
HURT: 0
total cycles in shared programs: 219476091 -> 219476059 (-0.00%)
cycles in affected programs: 7675 -> 7643 (-0.42%)
helped: 10
HURT: 1
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Since we know what side of the branch we ended up on we can just
replace the use with a constant.
All the spill changes in shader-db are from Dolphin uber shaders,
despite some small regressions the change is clearly positive.
V2: insert new constant after any phis in the
use->parent_instr->type == nir_instr_type_phi path.
v3:
- use nir_after_block_before_jump() for inserting const
- check dominance of phi uses correctly
v4:
- create some helpers as suggested by Jason.
v5 (Jason Ekstrand):
- Use LIST_ENTRY to get the phi src
shader-db results IVB:
total instructions in shared programs: 9999201 -> 9993483 (-0.06%)
instructions in affected programs: 163235 -> 157517 (-3.50%)
helped: 132
HURT: 2
total cycles in shared programs: 231670754 -> 219476091 (-5.26%)
cycles in affected programs: 143424120 -> 131229457 (-8.50%)
helped: 115
HURT: 24
total spills in shared programs: 4383 -> 4370 (-0.30%)
spills in affected programs: 1656 -> 1643 (-0.79%)
helped: 9
HURT: 18
total fills in shared programs: 4610 -> 4581 (-0.63%)
fills in affected programs: 374 -> 345 (-7.75%)
helped: 6
HURT: 0
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Only used, when asserts are enabled.
Fixes an unused-variable warning with gcc-8:
../../../src/compiler/nir/nir_opt_if.c: In function 'opt_peel_loop_initial_if':
../../../src/compiler/nir/nir_opt_if.c:109:15: warning: unused variable 'prev_block' [-Wunused-variable]
nir_block *prev_block =
^~~~~~~~~~
Signed-off-by: Kai Wasserbäch <kai@dev.carbon-project.org>
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
There always is a continue block, so let us just do unreachable.
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Fixes: 8cacf38f52 "nir: Do not use continue block after removing it."
CC: 18.1 <mesa-stable@lists.freedesktop.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107312
Reinserting code directly before a jump means the block gets split
and merged, removing the original block and replacing it in the
process.
Hence keeping a pointer to the continue block over a reinsert
causes issues.
This code changes nir_opt_if to simply look for the new continue
block.
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107275
CC: 18.1 <mesa-stable@lists.freedesktop.org>
It wasn't causing problems since there's nothing to delete, but better
be consistent with the rest of existing codebase.
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Now that SSA values can be derefs and they have special rules, we have
to be a bit more careful about our LCSSA phis. In particular, we need
to clean up in case LCSSA ended up creating a phi node for a deref.
This fixes validation issues with some Vulkan CTS tests with the new
deref instructions.
Reviewed-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>
This pass detects potential loop terminators and moves intructions
from the non breaking branch after the if-statement.
This enables both the new opt_if_simplification() pass and loop
unrolling to potentially progress further.
Unexpectedly this change speed up shader-db run times by ~3%
Ivy Bridge shader-db results (all changes in dolphin/ubershaders):
total instructions in shared programs: 9995662 -> 9995338 (-0.00%)
instructions in affected programs: 87845 -> 87521 (-0.37%)
helped: 27
HURT: 0
total cycles in shared programs: 230931495 -> 230925015 (-0.00%)
cycles in affected programs: 56391385 -> 56384905 (-0.01%)
helped: 27
HURT: 0
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
This pass turns:
if (cond) {
} else {
do_work();
}
into:
if (!cond) {
do_work();
} else {
}
Here's the vkpipeline-db stats (from affected shaders) on Polaris10:
Totals from affected shaders:
SGPRS: 17272 -> 17296 (0.14 %)
VGPRS: 18712 -> 18740 (0.15 %)
Spilled SGPRs: 1179 -> 1142 (-3.14 %)
Code Size: 1503364 -> 1515176 (0.79 %) bytes
Max Waves: 916 -> 911 (-0.55 %)
This pass only affects Serious Sam 2017 (Vulkan) on my side. The
stats are not really good for now. Some shaders look quite dumb
but this will be improved with further NIR passes, like ifs
combination.
Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
When shaders come in from SPIR-V, we handle continue blocks by placing
the contents of the continue inside of a "if (!first_iteration)". We do
this so that we can properly handle the fact that continues in SPIR-V
jump to the continue block at the end of the loop rather than jumping
directly to the top of the loop like they do in NIR. In particular, the
increment step of a simple for loop ends up in the continue block. This
pass looks for this case in loops that don't actually have any continues
and moves the continue contents to the end of the loop instead. We need
this because loop unrolling doesn't work if the increment is inside of a
condition.
Reviewed-by: Timothy Arceri <timothy.arceri@collabora.com>
