| #! /usr/bin/env python |
| # |
| # Copyright (C) 2016 Intel Corporation |
| # |
| # Permission is hereby granted, free of charge, to any person obtaining a |
| # copy of this software and associated documentation files (the "Software"), |
| # to deal in the Software without restriction, including without limitation |
| # the rights to use, copy, modify, merge, publish, distribute, sublicense, |
| # and/or sell copies of the Software, and to permit persons to whom the |
| # Software is furnished to do so, subject to the following conditions: |
| # |
| # The above copyright notice and this permission notice (including the next |
| # paragraph) shall be included in all copies or substantial portions of the |
| # Software. |
| # |
| # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| # THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
| # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS |
| # IN THE SOFTWARE. |
| |
| import nir_algebraic |
| |
| # Prior to Kaby Lake, The SIN and COS instructions on Intel hardware can |
| # produce values slightly outside of the [-1.0, 1.0] range for a small set of |
| # values. Obviously, this can break everyone's expectations about trig |
| # functions. This appears to be fixed in Kaby Lake. |
| # |
| # According to an internal presentation, the COS instruction can produce |
| # a value up to 1.000027 for inputs in the range (0.08296, 0.09888). One |
| # suggested workaround is to multiply by 0.99997, scaling down the |
| # amplitude slightly. Apparently this also minimizes the error function, |
| # reducing the maximum error from 0.00006 to about 0.00003. |
| |
| trig_workarounds = [ |
| (('fsin', 'x'), ('fmul', ('fsin', 'x'), 0.99997)), |
| (('fcos', 'x'), ('fmul', ('fcos', 'x'), 0.99997)), |
| ] |
| |
| print '#include "brw_nir.h"' |
| print nir_algebraic.AlgebraicPass("brw_nir_apply_trig_workarounds", |
| trig_workarounds).render() |
