On 05/12/2018 19:31, Connor Abbott wrote:
> On Wed, Dec 5, 2018 at 4:56 PM Samuel Iglesias Gonsálvez
> <sigles...@igalia.com> wrote:
>>
>> According to VK_KHR_shader_float_controls:
>>
>> "Denormalized values obtained via unpacking an integer into a vector
>> of values with smaller bit width and interpreting those values as
>> floating-point numbers must: be flushed to zero, unless the entry point
>> is declared with the code:DenormPreserve execution mode."
>>
>> Signed-off-by: Samuel Iglesias Gonsálvez <sigles...@igalia.com>
>> ---
>> src/compiler/nir/nir_constant_expressions.py | 13 +++++++++++++
>> src/compiler/nir/nir_lower_alu_to_scalar.c | 10 ++++++++--
>> src/compiler/nir/nir_opcodes.py | 5 +++++
>> 3 files changed, 26 insertions(+), 2 deletions(-)
>>
>> diff --git a/src/compiler/nir/nir_constant_expressions.py
>> b/src/compiler/nir/nir_constant_expressions.py
>> index a9af1bd233d..bc60a08da28 100644
>> --- a/src/compiler/nir/nir_constant_expressions.py
>> +++ b/src/compiler/nir/nir_constant_expressions.py
>> @@ -245,6 +245,19 @@ pack_half_1x16(float x)
>> return _mesa_float_to_half(x);
>> }
>>
>> +/**
>> + * Evaluate one component of unpackHalf2x16.
>> + */
>> +static float
>> +unpack_half_1x16_flush_to_zero(uint16_t u)
>> +{
>> + if (u < 0x0400)
>> + u = 0;
>> + if (u & 0x8000 && !(u & 0x7c00))
>> + u = 0x8000;
>> + return _mesa_half_to_float(u);
>> +}
>> +
>> /**
>> * Evaluate one component of unpackHalf2x16.
>> */
>> diff --git a/src/compiler/nir/nir_lower_alu_to_scalar.c
>> b/src/compiler/nir/nir_lower_alu_to_scalar.c
>> index 7ef032cd164..d80cf2504c7 100644
>> --- a/src/compiler/nir/nir_lower_alu_to_scalar.c
>> +++ b/src/compiler/nir/nir_lower_alu_to_scalar.c
>> @@ -133,8 +133,14 @@ lower_alu_instr_scalar(nir_alu_instr *instr,
>> nir_builder *b)
>> nir_ssa_def *packed = nir_ssa_for_alu_src(b, instr, 0);
>>
>> nir_ssa_def *comps[2];
>> - comps[0] = nir_unpack_half_2x16_split_x(b, packed);
>> - comps[1] = nir_unpack_half_2x16_split_y(b, packed);
>> +
>> + if (b->shader->info.shader_float_controls_execution_mode &
>> SHADER_DENORM_FLUSH_TO_ZERO_FP16) {
>> + comps[0] = nir_unpack_half_2x16_split_x_flush_to_zero(b, packed);
>> + comps[1] = nir_unpack_half_2x16_split_y_flush_to_zero(b, packed);
>
> This feels a little wrong... I think either we should add a
> nir_op_unpack_half_2x16_flush_to_zero, or we shouldn't be changing
> this here. We should be consistent on whether the flushing behavior is
> implied by the environment or specified by the opcode.
>
Right, I am going to add it.
Thanks!
Sam
>> + } else {
>> + comps[0] = nir_unpack_half_2x16_split_x(b, packed);
>> + comps[1] = nir_unpack_half_2x16_split_y(b, packed);
>> + }
>> nir_ssa_def *vec = nir_vec(b, comps, 2);
>>
>> nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, nir_src_for_ssa(vec));
>> diff --git a/src/compiler/nir/nir_opcodes.py
>> b/src/compiler/nir/nir_opcodes.py
>> index eb554a66b44..191025f6932 100644
>> --- a/src/compiler/nir/nir_opcodes.py
>> +++ b/src/compiler/nir/nir_opcodes.py
>> @@ -309,6 +309,11 @@ unop_convert("unpack_half_2x16_split_x", tfloat32,
>> tuint32,
>> unop_convert("unpack_half_2x16_split_y", tfloat32, tuint32,
>> "unpack_half_1x16((uint16_t)(src0 >> 16))")
>>
>> +unop_convert("unpack_half_2x16_split_x_flush_to_zero", tfloat32, tuint32,
>> + "unpack_half_1x16_flush_to_zero((uint16_t)(src0 & 0xffff))")
>> +unop_convert("unpack_half_2x16_split_y_flush_to_zero", tfloat32, tuint32,
>> + "unpack_half_1x16_flush_to_zero((uint16_t)(src0 >> 16))")
>> +
>> unop_convert("unpack_32_2x16_split_x", tuint16, tuint32, "src0")
>> unop_convert("unpack_32_2x16_split_y", tuint16, tuint32, "src0 >> 16")
>>
>> --
>> 2.19.1
>>
>> _______________________________________________
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>> mesa-dev@lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/mesa-dev
>
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