[Mesa-dev] [PATCH v2 020/103] i965/vec4: don't copy propagate vector opcodes that operate in align1 mode

[Ian Romanick]

This patch is

Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>

On 10/11/2016 02:01 AM, Iago Toral Quiroga wrote:
> Basically, ALIGN1 mode will ignore swizzles on the input vectors so we don't
> want the copy propagation pass to mess with them.
> ---
>  .../drivers/dri/i965/brw_vec4_copy_propagation.cpp | 24 ++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 
> diff --git a/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp b/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp
> index 545f4c7..d0045a7 100644
> --- a/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp
> @@ -283,6 +283,22 @@ try_constant_propagate(const struct gen_device_info *devinfo,
>  }
>  
>  static bool
> +is_align1_opcode(unsigned opcode)
> +{
> +   switch (opcode) {
> +   case VEC4_OPCODE_DOUBLE_TO_FLOAT:
> +   case VEC4_OPCODE_FLOAT_TO_DOUBLE:
> +   case VEC4_OPCODE_PICK_LOW_32BIT:
> +   case VEC4_OPCODE_PICK_HIGH_32BIT:
> +   case VEC4_OPCODE_SET_LOW_32BIT:
> +   case VEC4_OPCODE_SET_HIGH_32BIT:
> +      return true;
> +   default:
> +      return false;
> +   }
> +}
> +
> +static bool
>  try_copy_propagate(const struct gen_device_info *devinfo,
>                     vec4_instruction *inst, int arg,
>                     const copy_entry *entry, int attributes_per_reg)
> @@ -326,6 +342,14 @@ try_copy_propagate(const struct gen_device_info *devinfo,
>  
>     unsigned composed_swizzle = brw_compose_swizzle(inst->src[arg].swizzle,
>                                                     value.swizzle);
> +
> +   /* Instructions that operate on vectors in ALIGN1 mode will ignore swizzles
> +    * so copy-propagation won't be safe if the composed swizzle is anything
> +    * other than the identity.
> +    */
> +   if (is_align1_opcode(inst->opcode) && composed_swizzle != BRW_SWIZZLE_XYZW)
> +      return false;
> +
>     if (inst->is_3src(devinfo) &&
>         (value.file == UNIFORM ||
>          (value.file == ATTR && attributes_per_reg != 1)) &&
>