Fixes piglit tests (new in piglit!110):
- fs-underflow-fma-compare-zero.shader_test
- fs-underflow-mul-compare-zero.shader_test
v2: Add back part of comment accidentally deleted. Noticed by
Caio. Remove is_not_zero function as it is no longer used.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111308
Fixes: fa116ce357 ("nir/range-analysis: Range tracking for ffma and flrp")
Fixes: 405de7ccb6 ("nir/range-analysis: Rudimentary value range analysis pass")
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
All Gen7+ platforms** had similar results. (Ice Lake shown)
total instructions in shared programs: 16278465 -> 16279492 (<.01%)
instructions in affected programs: 16765 -> 17792 (6.13%)
helped: 0
HURT: 23
HURT stats (abs) min: 7 max: 275 x̄: 44.65 x̃: 8
HURT stats (rel) min: 1.15% max: 17.51% x̄: 4.23% x̃: 1.62%
95% mean confidence interval for instructions value: 9.57 79.74
95% mean confidence interval for instructions %-change: 1.85% 6.61%
Instructions are HURT.
total cycles in shared programs: 367135159 -> 367154270 (<.01%)
cycles in affected programs: 279306 -> 298417 (6.84%)
helped: 0
HURT: 23
HURT stats (abs) min: 13 max: 6029 x̄: 830.91 x̃: 54
HURT stats (rel) min: 0.17% max: 45.67% x̄: 7.33% x̃: 0.49%
95% mean confidence interval for cycles value: 100.89 1560.94
95% mean confidence interval for cycles %-change: 0.94% 13.71%
Cycles are HURT.
total spills in shared programs: 8870 -> 8869 (-0.01%)
spills in affected programs: 19 -> 18 (-5.26%)
helped: 1
HURT: 0
total fills in shared programs: 21904 -> 21901 (-0.01%)
fills in affected programs: 81 -> 78 (-3.70%)
helped: 1
HURT: 0
LOST: 0
GAINED: 1
** On Broadwell, a shader was hurt for spills / fills instead of
helped.
No changes on any earlier platforms.
A similar technique could be used for fmin3, fmax3, and fmid3.
This could be squashed with the previous commit. I kept it separate to
ease review.
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
This could be squashed with the previous commit. I kept it separate to
ease review.
v2: Add some missing cases. Use nir_src_is_const helper. Both
suggested by Caio. Use a table for mapping source ranges to a result
range.
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
This could be squashed with the previous commit. I kept it separate to
ease review.
v2: Use a switch statement and add more comments. Both suggested by
Caio.
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Most integer operations are omitted because dealing with integer
overflow is hard. There are a few things that could be smarter if there
was a small amount more tracking of ranges of integer types (i.e.,
operands are Boolean, operand values fit in 16 bits, etc.).
The changes to nir_search_helpers.h are included in this patch to
simplify reordering the changes to nir_opt_algebraic.py.
v2: Memoize range analysis results. Without this, some shaders appear
to get stuck in infinite loops.
v3: Rebase on many months of Mesa changes, including 1-bit Boolean
changes.
v4: Rebase on "nir: Drop imov/fmov in favor of one mov instruction".
v5: Use nir_alu_srcs_equal for detecting (a*a). Previously just the SSA
value was compared, and this incorrectly matched (a.x*a.y).
v6: Many code improvements including (but not limited to) better names,
more comments, and better use of helper functions. All suggested by
Caio. Rework the handling of several opcodes to use a table for mapping
source ranges to a result range. This change fixed a bug that caused
fmax(gt_zero, ge_zero) to be incorrectly recognized as ge_zero.
Slightly tighten the range of fmul by recognizing that x*x is gt_zero if
x is gt_zero. Add similar handling for -x*x.
v7: Use _______ in the tables as an alias for unknown. Suggested by
Caio.
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
