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54 lines
2.1 KiB
Python
54 lines
2.1 KiB
Python
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# Copyright © 2024 Intel Corporation
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# SPDX-License-Identifier: MIT
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import argparse
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import sys
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from math import pi
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a = 'a'
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b = 'b'
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lower_fsign = [
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# This matches the behavior of the old optimization in brw_fs_nir.cpp, but
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# it has some problems.
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#
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# The fmul version passes Vulkan float_controls2 CTS a little bit by
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# luck. The use of fne means that the false path (i.e., fsign(X) == 0) is
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# only taken when X is zero. For OpenCL, this path should also be taken
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# when when X is NaN. This can be handled by using 'fabs(X) > 0', but this
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# fails float_controls2 CTS when the other multiplication operand is NaN.
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#
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# This optimization is additionally problematic when fsign(X) is zero and
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# the other multiplication operand is Inf. This will result in 0, but it
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# should result in NaN. This does not seem to be tested by the CTS.
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#
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# NOTE: fcsel opcodes are currently limited to float32 in NIR.
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(('fmul@32', ('fsign(is_used_once)', a), b), ('fcsel', a , ('ixor', ('iand', a, 0x80000000), b), ('iand', a, 0x80000000))),
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(('fmul@16', ('fsign(is_used_once)', a), b), ('bcsel', ('fneu', a, 0), ('ixor', ('iand', a, 0x8000 ), b), ('iand', a, 0x8000 ))),
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# This is 99.99% strictly correct for OpenCL. It will provide correctly
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# signed zero for ±0 inputs, and it will provide zero for NaN inputs. The
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# only slight deviation is that it can provide -0 for some NaN inputs.
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(('fsign@32', a), ('fcsel_gt', ('fabs', a) , ('ior', ('iand', a, 0x80000000), 0x3f800000), ('iand', a, 0x80000000))),
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(('fsign@16', a), ('bcsel', ('!flt', 0, ('fabs', a)), ('ior', ('iand', a, 0x8000 ), 0x3c00 ), ('iand', a, 0x8000 ))),
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]
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def main():
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parser = argparse.ArgumentParser()
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parser.add_argument('-p', '--import-path', required=True)
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args = parser.parse_args()
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sys.path.insert(0, args.import_path)
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run()
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def run():
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import nir_algebraic # pylint: disable=import-error
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print('#include "brw_nir.h"')
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print(nir_algebraic.AlgebraicPass("brw_nir_lower_fsign", lower_fsign).render())
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if __name__ == '__main__':
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main()
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