[Mesa-dev] [PATCH 28/59] intel/compiler: set correct precision fields for 3-source float instructions

[Pohjolainen, Topi]

On Tue, Dec 04, 2018 at 08:16:52AM +0100, Iago Toral Quiroga wrote:
> Source0 and Destination extract the floating-point precision automatically
> from the SrcType and DstType instruction fields respectively when they are
> set to types :F or :HF. For Source1 and Source2 operands, we use the new
> 1-bit fields Src1Type and Src2Type, where 0 means normal precision and 1
> means half-precision. Since we always use the type of the destination for
> all operands when we emit 3-source instructions, we only need set Src1Type
> and Src2Type to 1 when we are emitting a half-precision instruction.
> ---
>  src/intel/compiler/brw_eu_emit.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/src/intel/compiler/brw_eu_emit.c b/src/intel/compiler/brw_eu_emit.c
> index 2c9fc9a5c7c..66edfb43baf 100644
> --- a/src/intel/compiler/brw_eu_emit.c
> +++ b/src/intel/compiler/brw_eu_emit.c
> @@ -801,6 +801,11 @@ brw_alu3(struct brw_codegen *p, unsigned opcode, struct brw_reg dest,
>            */
>           brw_inst_set_3src_a16_src_type(devinfo, inst, dest.type);
>           brw_inst_set_3src_a16_dst_type(devinfo, inst, dest.type);
> +
> +         if (devinfo->gen >= 8 && dest.type == BRW_REGISTER_TYPE_HF) {
> +            brw_inst_set_3src_a16_src1_type(devinfo, inst, 1);
> +            brw_inst_set_3src_a16_src2_type(devinfo, inst, 1);
> +         }

I had similar patch which prepares for mixed mode (useful for linterp with
32-bit input varyings):

         /* From the Bspec: Instruction types
          *
          * Three source instructions can use operands with mixed-mode
          * precision. When SrcType field is set to :f or :hf it defines
          * precision for source 0 only, and fields Src1Type and Src2Type
          * define precision for other source operands:
          *
          *   0b = :f. Single precision Float (32-bit).
          *   1b = :hf. Half precision Float (16-bit).
          */
         if (src1.type == BRW_REGISTER_TYPE_HF)
            brw_inst_set_3src_src1_type(devinfo, inst, 1);

         if (src2.type == BRW_REGISTER_TYPE_HF)
            brw_inst_set_3src_src2_type(devinfo, inst, 1);

How would you feel about that? (Direct cut-paste and the helpers have
different name).

>        }
>     }
>  
> -- 
> 2.17.1
> 
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