On 12/03/18 20:42, Jason Ekstrand wrote: > On Mon, Mar 5, 2018 at 10:21 PM, Samuel Iglesias Gonsálvez > <sigles...@igalia.com <mailto:sigles...@igalia.com>> wrote: > > OpSConvert interprets the MSB of the unsigned value as the sign > bit and > extends it to the new type. If we want to preserve the value, we need > to use OpUConvert opcode. > > v2: > - No need to check dst type. > - Fix typo in comment. > > Signed-off-by: Samuel Iglesias Gonsálvez <sigles...@igalia.com > <mailto:sigles...@igalia.com>> > --- > src/compiler/spirv/vtn_alu.c | 18 +++++++++++++++++- > 1 file changed, 17 insertions(+), 1 deletion(-) > > diff --git a/src/compiler/spirv/vtn_alu.c > b/src/compiler/spirv/vtn_alu.c > index d0c9e316935..a5cefc35773 100644 > --- a/src/compiler/spirv/vtn_alu.c > +++ b/src/compiler/spirv/vtn_alu.c > @@ -354,10 +354,26 @@ vtn_nir_alu_op_for_spirv_opcode(struct > vtn_builder *b, > case SpvOpConvertFToS: > case SpvOpConvertSToF: > case SpvOpConvertUToF: > - case SpvOpSConvert: > case SpvOpFConvert: > return nir_type_conversion_op(src, dst, > nir_rounding_mode_undef); > > + case SpvOpSConvert: { > + nir_alu_type src_base = (nir_alu_type) > nir_alu_type_get_base_type(src); > + if (src_base == nir_type_uint) { > > > Why are we predicating this on src_base == nir_type_uint? It seems to > me as if we should just ignore the source and destination type except > for the bit size.
Right.
>
>
> + /* SPIR-V expects to interpret the unsigned value as
> signed and
> + * do sign extend. Return the opcode accordingly.
> + */
> + unsigned dst_bit_size = nir_alu_type_get_type_size(dst);
> + switch (dst_bit_size) {
> + case 16: return nir_op_i2i16;
> + case 32: return nir_op_i2i32;
> + case 64: return nir_op_i2i64;
>
>
> This can be nir_type_int | dst_bit_size. NIR types are convenient like
> that. :-)
Oh, nice suggestion! I am going to send soon a v3 with the suggested
changes for both patches.
Thanks a lot!
Sam
>
>
> + default:
> + vtn_fail("Invalid nir alu bit size");
> + }
> + }
> + return nir_type_conversion_op(src, dst,
> nir_rounding_mode_undef);
> + }
> /* Derivatives: */
> case SpvOpDPdx: return nir_op_fddx;
> case SpvOpDPdy: return nir_op_fddy;
> --
> 2.14.1
>
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