This doesn't help on Intel GPUs now because we always take the
"always_precise" path first. It may help on other GPUs, and it does
prevent a bunch of regressions in "intel/compiler: Don't always require
precise lowering of flrp".
Reviewed-by: Matt Turner <mattst88@gmail.com>
There is little effect on Intel GPUs now because we almost always take
the "always_precise" path first. It may help on other GPUs, and it does
prevent a bunch of regressions in "intel/compiler: Don't always require
precise lowering of flrp".
No changes on any other Intel platforms.
GM45 and Iron Lake had similar results. (Iron Lake shown)
total cycles in shared programs: 188852500 -> 188852484 (<.01%)
cycles in affected programs: 14612 -> 14596 (-0.11%)
helped: 4
HURT: 0
helped stats (abs) min: 4 max: 4 x̄: 4.00 x̃: 4
helped stats (rel) min: 0.09% max: 0.13% x̄: 0.11% x̃: 0.11%
95% mean confidence interval for cycles value: -4.00 -4.00
95% mean confidence interval for cycles %-change: -0.13% -0.09%
Cycles are helped.
Reviewed-by: Matt Turner <mattst88@gmail.com>
This doesn't help on Intel GPUs now because we always take the
"always_precise" path first. It may help on other GPUs, and it does
prevent a bunch of regressions in "intel/compiler: Don't always require
precise lowering of flrp".
No changes on any Intel platform. Before a number of large rebases this
helped cycles in a couple shaders on Iron Lake and GM45.
Reviewed-by: Matt Turner <mattst88@gmail.com>
If the magnitudes of #a and #b are such that (b-a) won't lose too much
precision, lower as a+c(b-a).
No changes on any other Intel platforms.
v2: Rebase on 424372e5dd5 ("nir: Use the flrp lowering pass instead of
nir_opt_algebraic")
Iron Lake and GM45 had similar results. (Iron Lake shown)
total instructions in shared programs: 8192503 -> 8192383 (<.01%)
instructions in affected programs: 18417 -> 18297 (-0.65%)
helped: 68
HURT: 0
helped stats (abs) min: 1 max: 18 x̄: 1.76 x̃: 1
helped stats (rel) min: 0.19% max: 7.89% x̄: 1.10% x̃: 0.43%
95% mean confidence interval for instructions value: -2.48 -1.05
95% mean confidence interval for instructions %-change: -1.56% -0.63%
Instructions are helped.
total cycles in shared programs: 188662536 -> 188661956 (<.01%)
cycles in affected programs: 744476 -> 743896 (-0.08%)
helped: 62
HURT: 0
helped stats (abs) min: 4 max: 60 x̄: 9.35 x̃: 6
helped stats (rel) min: 0.02% max: 4.84% x̄: 0.27% x̃: 0.06%
95% mean confidence interval for cycles value: -12.37 -6.34
95% mean confidence interval for cycles %-change: -0.48% -0.06%
Cycles are helped.
Reviewed-by: Matt Turner <mattst88@gmail.com>
This pass will soon grow to include some optimizations that are
difficult or impossible to implement correctly within nir_opt_algebraic.
It also include the ability to generate strictly correct code which the
current nir_opt_algebraic lowering lacks (though that could be changed).
v2: Document the parameters to nir_lower_flrp. Rebase on top of
3766334923 ("compiler/nir: add lowering for 16-bit flrp")
Reviewed-by: Matt Turner <mattst88@gmail.com>
