diff options
| -rw-r--r-- | src/compiler/nir/nir_opt_algebraic.py | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/src/compiler/nir/nir_opt_algebraic.py b/src/compiler/nir/nir_opt_algebraic.py index 9b82bac6f6c..cc2c2299ab9 100644 --- a/src/compiler/nir/nir_opt_algebraic.py +++ b/src/compiler/nir/nir_opt_algebraic.py @@ -312,6 +312,19 @@ optimizations = [ 'options->lower_unpack_snorm_4x8'), ] +# Unreal Engine 4 demo applications open-codes bitfieldReverse() +def bitfield_reverse(u): + step1 = ('ior', ('ishl', u, 16), ('ushr', u, 16)) + step2 = ('ior', ('ishl', ('iand', step1, 0x00ff00ff), 8), ('ushr', ('iand', step1, 0xff00ff00), 8)) + step3 = ('ior', ('ishl', ('iand', step2, 0x0f0f0f0f), 4), ('ushr', ('iand', step2, 0xf0f0f0f0), 4)) + step4 = ('ior', ('ishl', ('iand', step3, 0x33333333), 2), ('ushr', ('iand', step3, 0xcccccccc), 2)) + step5 = ('ior', ('ishl', ('iand', step4, 0x55555555), 1), ('ushr', ('iand', step4, 0xaaaaaaaa), 1)) + + return step5 + +optimizations += [(bitfield_reverse('x'), ('bitfield_reverse', 'x'))] + + # Add optimizations to handle the case where the result of a ternary is # compared to a constant. This way we can take things like # |