[Mesa-dev] [PATCH 2/2] spirv: fix bug when OpSpecConstantOp calls a conversion

[Ian Romanick]

On 11/20/2017 10:25 PM, Samuel Iglesias Gonsálvez wrote:
> In that case, nir_eval_const_opcode() will evaluate the conversion
> but as it was using destination's bit_size, the resulting
> value was just a cast of the source constant value. By passing the
> source's bit size, it does the conversion properly.
> 
> Fixes:
> 
> dEQP-VK.spirv_assembly.instruction.*.opspecconstantop.*convert*
> 
> Signed-off-by: Samuel Iglesias Gonsálvez <siglesias at igalia.com>
> ---
>  src/compiler/spirv/spirv_to_nir.c | 31 ++++++++++++++++++++++++++-----
>  1 file changed, 26 insertions(+), 5 deletions(-)
> 
> diff --git a/src/compiler/spirv/spirv_to_nir.c b/src/compiler/spirv/spirv_to_nir.c
> index 2cc3c275ea9..ffbda4f1946 100644
> --- a/src/compiler/spirv/spirv_to_nir.c
> +++ b/src/compiler/spirv/spirv_to_nir.c
> @@ -1348,14 +1348,35 @@ vtn_handle_constant(struct vtn_builder *b, SpvOp opcode,
>           bool swap;
>           nir_alu_type dst_alu_type = nir_get_nir_type_for_glsl_type(val->const_type);
>           nir_alu_type src_alu_type = dst_alu_type;
> -         nir_op op = vtn_nir_alu_op_for_spirv_opcode(opcode, &swap, src_alu_type, dst_alu_type);
> -
>           unsigned num_components = glsl_get_vector_elements(val->const_type);
> -         unsigned bit_size =
> -            glsl_get_bit_size(val->const_type);
> +         unsigned bit_size;
>  
> -         nir_const_value src[4];
>           assert(count <= 7);
> +
> +         switch (opcode) {
> +         case SpvOpUConvert:
> +         case SpvOpConvertFToU:
> +         case SpvOpConvertFToS:
> +         case SpvOpConvertSToF:
> +         case SpvOpConvertUToF:
> +         case SpvOpSConvert:
> +         case SpvOpFConvert:

I'm not sure what we should do here.  Most of these opcodes are not
valid in SpvOpSpecConstantOp in a Shader.  Only SpvOpSConvert and
SpvOpFConvert are allowed.  I guess it's trivial enough to support the
others anyway... do those dEQP-VK.spirv_assembly.instruction.* tests
exercise the other opcodes?

> +            /* We have a source in a conversion */
> +            src_alu_type =
> +               nir_get_nir_type_for_glsl_type(
> +                  vtn_value(b, w[4], vtn_value_type_constant)->const_type);
> +            /* We use the bitsize of the conversion source to evaluate the opcode later */
> +            bit_size = glsl_get_bit_size(
> +               vtn_value(b, w[4], vtn_value_type_constant)->const_type);
> +            break;
> +         default:
> +            bit_size = glsl_get_bit_size(val->const_type);
> +         };
> +
> +
> +         nir_op op = vtn_nir_alu_op_for_spirv_opcode(opcode, &swap, src_alu_type, dst_alu_type);
> +         nir_const_value src[4];
> +
>           for (unsigned i = 0; i < count - 4; i++) {
>              nir_constant *c =
>                 vtn_value(b, w[4 + i], vtn_value_type_constant)->constant;
>