spir-v: Mark floating point comparisons exact
OpenGL GLSL, OpenGL ARB assembly shaders, and DX9 are pretty loose about
the behavior in the presence of NaNs. Many GPUs that implement these
specifications do not even have a representation of NaN. However,
OpenCL and Vulkan SPIR-V are not so lax. Both actually have some
required behavior in the presence of NaN, and, of the two, OpenCL is the
most strict.
For years we have implemented SPIR-V by using the same comparison
opcodes as we use for OpenGL GLSL and OpenGL assembly shaders. This has
repeatedly caused problems where an optimization that is valid in the
NaN-relaxed world is not valid in Vulkan or OpenCL. To fix this, set
the "exact" flag on comparisons instructions generated from SPIR-V.
This will block optimizations that may have different NaN behavior.
v2: Set the exact flag in the nir_builder, not in the vtn_builder.
v3: Add an assertion in vtn_handle_constant that the exact flag wasn't
set (because it's ignored). Rebase on 80163bbec3a ("nir/vtn: Support
OpOrdered and OpUnordered opcodes"). Mark the NIR generated for those
opcodes as exact as well.
v4: s/unused_exact/exact/ in a couple places, and assert that exact has
the expected value (true in one place, false in the other). Suggested
by Caio.
Closes: #3345
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Tested-by: Danylo Piliaiev <danylo.piliaiev@globallogic.com>
Fixes: 8513b12590c ("nir/opt_if: split ALU from Phi more aggressively")
This commit doesn't really fix anything in 8513b12590c. However,
without 8513b12590c, a regression is triggered in RADV on No Man's
Sky. I want to ensure that this change is only applied on top of
8513b12590c, and Fixes: seems the safest way to do that.
No shader-db changes on any Intel platform. This only affects SPIR-V,
and we have no OpenGL SPIR-V shaders in shader-db.
124 shaders in Shadow of the Tomb Raider (Steam "native") were hurt by 1
spill and 1 fill each.
All Intel platforms had similar results. (Tiger Lake shown)
Instructions in all programs: 155668276 -> 155685764 (+0.0%)
SENDs in all programs: 6474570 -> 6474570 (+0.0%)
Loops in all programs: 35271 -> 35271 (+0.0%)
Cycles in all programs: 3198055373 -> 3198628031 (+0.0%)
Spills in all programs: 231522 -> 231646 (+0.1%)
Fills in all programs: 347571 -> 347695 (+0.0%)
Vega
Totals:
SGPRs: 20955712 -> 20956756 (+0.00%); split: -0.02%, +0.03%
VGPRs: 13476920 -> 13473132 (-0.03%); split: -0.07%, +0.04%
CodeSize: 613371940 -> 613339348 (-0.01%); split: -0.06%, +0.05%
MaxWaves: 3111886 -> 3112481 (+0.02%); split: +0.02%, -0.00%
Instrs: 120723785 -> 120746991 (+0.02%); split: -0.04%, +0.06%
Cycles: 626658992 -> 626862708 (+0.03%); split: -0.05%, +0.08%
VMEM: 216330854 -> 216343196 (+0.01%); split: +0.04%, -0.04%
SMEM: 32079391 -> 32081972 (+0.01%); split: +0.05%, -0.04%
VClause: 2688784 -> 2688789 (+0.00%); split: -0.03%, +0.03%
SClause: 6554669 -> 6556251 (+0.02%); split: -0.01%, +0.03%
Copies: 5356667 -> 5353283 (-0.06%); split: -0.36%, +0.29%
Branches: 954466 -> 954716 (+0.03%); split: -0.01%, +0.04%
PreSGPRs: 9078300 -> 9081626 (+0.04%); split: -0.01%, +0.05%
PreVGPRs: 10972090 -> 10966576 (-0.05%); split: -0.06%, +0.01%
Totals from 48239 (12.08% of 399432) affected shaders:
SGPRs: 2713984 -> 2715028 (+0.04%); split: -0.16%, +0.19%
VGPRs: 1997804 -> 1994016 (-0.19%); split: -0.46%, +0.27%
CodeSize: 172094092 -> 172061500 (-0.02%); split: -0.21%, +0.19%
MaxWaves: 337327 -> 337922 (+0.18%); split: +0.20%, -0.02%
Instrs: 33053657 -> 33076863 (+0.07%); split: -0.15%, +0.22%
Cycles: 254961228 -> 255164944 (+0.08%); split: -0.12%, +0.20%
VMEM: 15165226 -> 15177568 (+0.08%); split: +0.59%, -0.51%
SMEM: 3304938 -> 3307519 (+0.08%); split: +0.49%, -0.41%
VClause: 766225 -> 766230 (+0.00%); split: -0.12%, +0.12%
SClause: 1332645 -> 1334227 (+0.12%); split: -0.04%, +0.16%
Copies: 2040651 -> 2037267 (-0.17%); split: -0.94%, +0.77%
Branches: 743668 -> 743918 (+0.03%); split: -0.01%, +0.05%
PreSGPRs: 1697667 -> 1700993 (+0.20%); split: -0.07%, +0.27%
PreVGPRs: 1718424 -> 1712910 (-0.32%); split: -0.39%, +0.07%
Polaris
Totals:
SGPRs: 21349172 -> 21354376 (+0.02%); split: -0.02%, +0.04%
VGPRs: 13690680 -> 13686920 (-0.03%); split: -0.07%, +0.04%
CodeSize: 613745824 -> 613704988 (-0.01%); split: -0.06%, +0.05%
MaxWaves: 2775012 -> 2775189 (+0.01%); split: +0.01%, -0.00%
Instrs: 120735079 -> 120756209 (+0.02%); split: -0.04%, +0.06%
Cycles: 627906100 -> 628076156 (+0.03%); split: -0.05%, +0.08%
VMEM: 216623065 -> 216641838 (+0.01%); split: +0.04%, -0.04%
SMEM: 32295618 -> 32299338 (+0.01%); split: +0.05%, -0.04%
VClause: 2711025 -> 2711141 (+0.00%); split: -0.03%, +0.04%
SClause: 6545185 -> 6546769 (+0.02%); split: -0.01%, +0.03%
Copies: 5387723 -> 5383249 (-0.08%); split: -0.37%, +0.29%
Branches: 953775 -> 953954 (+0.02%); split: -0.01%, +0.03%
PreSGPRs: 9148814 -> 9153211 (+0.05%); split: -0.01%, +0.06%
PreVGPRs: 11029429 -> 11023915 (-0.05%); split: -0.06%, +0.01%
Totals from 48239 (12.00% of 402052) affected shaders:
SGPRs: 2682056 -> 2687260 (+0.19%); split: -0.16%, +0.35%
VGPRs: 1994436 -> 1990676 (-0.19%); split: -0.46%, +0.27%
CodeSize: 170857060 -> 170816224 (-0.02%); split: -0.21%, +0.19%
MaxWaves: 295429 -> 295606 (+0.06%); split: +0.07%, -0.01%
Instrs: 32808802 -> 32829932 (+0.06%); split: -0.16%, +0.22%
Cycles: 254633252 -> 254803308 (+0.07%); split: -0.13%, +0.20%
VMEM: 14897934 -> 14916707 (+0.13%); split: +0.65%, -0.52%
SMEM: 3289726 -> 3293446 (+0.11%); split: +0.53%, -0.42%
VClause: 775318 -> 775434 (+0.01%); split: -0.11%, +0.13%
SClause: 1304867 -> 1306451 (+0.12%); split: -0.04%, +0.16%
Copies: 2026334 -> 2021860 (-0.22%); split: -0.99%, +0.77%
Branches: 742554 -> 742733 (+0.02%); split: -0.02%, +0.04%
PreSGPRs: 1690887 -> 1695284 (+0.26%); split: -0.07%, +0.33%
PreVGPRs: 1717709 -> 1712195 (-0.32%); split: -0.40%, +0.07%
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6358>
(cherry picked from commit 010e663cc3401c40182922a04af0719e1898cb62)
4 files changed
